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1: OTL Asylum, RE: Well, either will work.. but (0.00)
Posted by Legendre on 2011-09-18, 19:20:08 (71.195.44.31)
You can adjust the DC offset pretty much any time you like, but the amp needs to be warmed up and otherwise settled if you want the adjustment to hold. I think this should be a fairly intuitive concep .......
2: OTL Asylum, Well, either will work.. but (0.00)
Posted by Legendre on 2011-09-15, 10:29:19 (71.195.44.31)
You're probably best off using a low-current scale on the meter - 1A DC, 500mA DC, etc. Noise and other perturbations in the amplifier can make reading offset on a voltage scale an annoying, tail-chas .......
3: OTL Asylum, RE: And it came to pass that there was a parting of the ways (0.00)
Posted by Legendre on 2011-09-10, 18:49:21 (71.195.44.31)
Heya Duke, Thanks for the kind words, man. I've always enjoyed working with you, be it "official" business or just a friendly gab session. In my book, you've always been a great FOAS ('Friend of Atma .......
4: OTL Asylum, And it came to pass that there was a parting of the ways (0.00)
Posted by Legendre on 2011-09-09, 19:39:31 (71.195.44.31)
Atma-Sphere customers and other OTL friends - too many to list, As you may or may not be aware, several months ago I resigned my position as lead tech / shop supervisor at Atma-Sphere Music Systems af .......
5: OTL Asylum, RE: I did inspect the tube, and the 'fuses' looked no different... (0.00)
Posted by Legendre on 2011-06-13, 22:33:35 (71.195.44.31)
Ok, good to know. If the links look fine, but the section is totally dead AND the heater is still lighting up on that side, I'd try reflowing the solder in the associated base pins. I've seen this ki .......
6: OTL Asylum, RE: OTL amps, paralleled triodes, and dead sections (0.00)
Posted by Legendre on 2011-06-13, 21:02:16 (71.195.44.31)
Did you visually inspect the tube with the dead section, to see if the link was blown out? There should be a document for this procedure, on the Atma-Sphere website. Visual inspection is a very usefu .......
7: OTL Asylum, Legendre's Simple Guide to Atma tube positions (0.00)
Posted by Legendre on 2011-06-12, 07:11:54 (71.195.44.31)
Here's how to tell which driver tube is which, for basically any Atma-Sphere amp Mk.II or later. Take the bottom off the amp, and have a look: (Recall that octal tube socket pins are numbered in a clo .......
8: OTL Asylum, RE: Atma Cap Break-in patience required (0.00)
Posted by Legendre on 2011-06-09, 08:21:14 (71.195.44.31)
There seems to be a growing consensus that the V-Caps (nice parts, btw) do have a bit of a break-in characteristic. And I don't know how much was done to your MA-1 Deluxe (as those MA-2-like MA-1 are .......
9: OTL Asylum, Yep, that's how it's done. (0.00)
Posted by Legendre on 2011-06-09, 08:03:20 (71.195.44.31)
Generally speaking, more, smaller caps = lower total inductance than fewer, larger caps. That, and it's a common-sense expedient for this physical layout. .......
10: OTL Asylum, FYI - that's not really the high voltage.. (0.00)
Posted by Legendre on 2011-06-09, 07:52:25 (71.195.44.31)
The second switch (on the right, with the red lamp, also known as the Standby switch) only controls the dual 160V B+ supplies for the output section. High voltage (+/-325V) is controlled by the Main p .......
11: Tubes Asylum, RE: thanks, a good site, yet... (0.00)
Posted by Legendre on 2011-06-08, 11:57:23 (71.195.44.31)
Check your email.. I sent you contact info for another seller. I'd have just posted it here, but I only know his home number - and he may not want it in plain view of the whole net.. ;-) .......
12: Tubes Asylum, RE: Miniwatt ECC82 source (0.00)
Posted by Legendre on 2011-06-08, 09:27:20 (71.195.44.31)
Have you tried www.tctubes.com? They're a newer outfit, but I know them to be reputable - and they have a no-questions return policy. .......
13: Tubes Asylum, Super glue for low-temp tubes, JB Weld for stuff that gets hot (0.00)
Posted by Legendre on 2011-06-07, 10:13:23 (71.195.44.31)
Conventional epoxies may also work, but I'd check the working temp range first. And as ever, surface prep is critical to ensuring a solid bond - irrespective of your chosen adhesive. .......
14: Tubes Asylum, RE: TungSol RI 6V6GT update.... #2 bad news, again ! (0.00)
Posted by Legendre on 2011-06-07, 10:08:17 (71.195.44.31)
In my case, it was EL34s, not 6V6s. And they may have been "Mullards" rather than "TungSols". Don't recall at the moment, it was a couple of years ago. And I'll be square with you - I'm seriously put .......
15: Tubes Asylum, RE: TungSol RI 6V6GT update.... #2 bad news, again ! (0.00)
Posted by Legendre on 2011-06-07, 07:56:35 (71.195.44.31)
Hey FenderLover, As you might have gathered, I'm extremely skeptical of these various New Sensor / EH "resissue" tubes. Sorry to hear you had trouble with the 6V6s, but your experience mirrors my own .......
16: Tubes Asylum, RE: TungSol RI 6V6GT update.... #2 bad news, again ! (0.00)
Posted by Legendre on 2011-06-07, 07:48:50 (71.195.44.31)
"Here is one case where the reissues have acted up." One more case. =p .......
17: Tubes Asylum, 6AQ5 (0.00)
Posted by Legendre on 2011-06-06, 08:01:58 (71.195.44.31)
Hi Tom, I briefly looked at the 6AQ5, but came to the conclusion that (in addition to the increased heater currents) it needed way more quiescent bias current than the ELL80 to run in a linear region .......
18: Tubes Asylum, It's a Fisher Philharmonic IV ca. 1964 if that helps /nt (0.00)
Posted by Legendre on 2011-06-05, 11:19:30 (71.195.44.31)
nt .......
19: Speaker Asylum, RE: Protection Capacitor (0.00)
Posted by Legendre on 2011-06-04, 18:13:00 (71.195.44.31)
From what you wrote, it sounds like you have it backwards. The larger the value (not rating) of the cap, the lower the bottom frequency of the passband. Every doubling of value correlates closely to a .......
20: Speaker Asylum, RE: Electro-Voice mini bookshelf LS - Any idea what model / era? (0.00)
Posted by Legendre on 2011-06-04, 13:33:31 (71.195.44.31)
The linked document doesn't mention any sort of EQ device, just connection directly to the amplifier outputs. .......
21: Tubes Asylum, Care to post a photo of yours? (0.00)
Posted by Legendre on 2011-06-04, 10:04:12 (71.195.44.31)
I'd like to get a better look at the plate structure. And how the heck did Phillips/ECG manage to mis-label a complete run of tubes? Any idea how many of these there are? TIA .......
22: Speaker Asylum, Brilliant, thank you! (0.00)
Posted by Legendre on 2011-06-04, 08:31:08 (71.195.44.31)
A pair of EV Model Eleven's they are indeed! My drivers look just like the one shown in your photo, so I guess they are original. One of the whizzers in my pair is a little crooked, though. Not sure i .......
23: Tubes Asylum, RE: Is this BS!!! (0.00)
Posted by Legendre on 2011-06-04, 07:38:55 (71.195.44.31)
I'm certainly no expert on this particular topic, but the tube in his photo doesn't appear to have a plate structure that resembles any 5AR4 that I've ever seen. .......
24: Speaker Asylum, Electro-Voice mini bookshelf LS - Any idea what model / era? (0.00)
Posted by Legendre on 2011-06-03, 18:05:47 (71.195.44.31)
Picked up this pair of little EV bookshelf speakers at a sale this afternoon. I didn't even know that EV made stuff like this. They're a ported bass-reflex design, with a single 6" paper cone drive .......
25: Tubes Asylum, Need Fisher 290T schematic / docs + EL95 tubes (0.00)
Posted by Legendre on 2011-06-03, 10:30:37 (71.195.44.31)
Came across a really mint Fisher 290T (Philharmonic console) unit yesterday. Couldn't pass it up for the tiny sum of $8, though someone had pilfered all of the knobs and vacuum tubes. Checked the usu .......
26: Tubes Asylum, RE: In lieu of a tube tester ... (0.00)
Posted by Legendre on 2011-05-25, 12:09:09 (24.131.182.81)
You can check filament continuity (pins 4,5,9) and test for cold shorts (between various combinations of other pins), but that's about it. No way to measure quality with *only* a multimeter. ::: TOPI .......
27: Tubes Asylum, Never heard of it. (0.00)
Posted by Legendre on 2011-05-25, 10:20:15 (24.131.182.81)
Never heard of it. Is it a miniature thyratron, like a 2D21? .......
28: Tubes Asylum, Not so much attitude, just a bit of confusion. (0.00)
Posted by Legendre on 2011-05-25, 08:51:31 (24.131.182.81)
Hi Michael, and thanks for forwarding those materials to Tre.. much appreciated. Now take a look at the accompanying image.. it looks like there are two of you. ;-) One Michael Norona (an unregist .......
29: Inmate Systems, Legendre's My system (0.00)
Posted by Legendre on 2011-05-25, 07:19:24 (24.131.182.81)
Legendre 's My system System
IP Address: 24.131.182.81
Last Update: May 25, 2011 at 07:19:24
Amplifier: Atma-Sphere M-60 Mk.III
Preamplifier (or None if Integrated): Atma-Sphere MP-1 M .......
30: Tubes Asylum, Do you realize that I have no way to "send" you my email? =) (0.00)
Posted by Legendre on 2011-05-23, 10:48:50 (71.195.16.24)
Doesn't seem that you're a registered user, so I cannot just click your name and send a mail. Hope you see this. .......
31: Tubes Asylum, If you don't have that bias probe handy.. (0.00)
Posted by Legendre on 2011-05-22, 21:20:08 (71.195.16.24)
"Going to borrow a friend's bias meter and double check the settings." You can always use the "ammeter across the transformer" method to check bias current. It only provides information about plate cu .......
32: Tubes Asylum, Is it fair to call these 'reissues'? (0.00)
Posted by Legendre on 2011-05-22, 19:05:10 (71.195.16.24)
For people like myself, who haven't had the chance to examine, play or measure these new 6V6s - how does the construction compare to the originals? Do the internal structures look the same, similar or .......
33: Tubes Asylum, RE: Michael, could you send me a copy also? (0.00)
Posted by Legendre on 2011-05-22, 18:48:27 (71.195.16.24)
Hey Tre', long time.. If you don't receive a copy, for whatever reason, let me know.. and I'll be very happy to forward one. I'm also becoming a big fan of the higher-end Triplett models, the 3423 an .......
34: Tubes Asylum, RE: Let's try this again - Looking for Triplett 3444 cal data / Michael Norona (0.00)
Posted by Legendre on 2011-05-22, 18:34:19 (71.195.16.24)
Ah, excellent! I've already grabbed everything from BAMA, so the only thing I'm lacking is the 3444 cal document. Thanks for uploading all of that stuff, by the way. I don't see any way to "send" you .......
35: Tubes Asylum, RE: Here you go! (0.00)
Posted by Legendre on 2011-05-22, 09:10:57 (76.17.237.41)
Thanks for the effort, Mike, and sorry for the confusion.. .......
36: Tubes Asylum, Let's try this again - Looking for Triplett 3444 cal data / Michael Norona (0.00)
Posted by Legendre on 2011-05-22, 08:36:09 (76.17.237.41)
Ok, let's try this again.. Does anyone have the cal data for the Triplett 3444 tube tester, or know how to get ahold of Mr. Michael Norona - who claimed to have it? Here's the original post where he o .......
37: Tubes Asylum, Doh! Not Mike Samra, Michael Norona! (0.00)
Posted by Legendre on 2011-05-22, 08:31:18 (76.17.237.41)
I'm such a dope.. It wasn't Mike Samra (thanks anyway, man) that I was looking for, but Mike Norona. I found the original post: http://www.audioasylum.com/audio/tubes/messages/23/232417.html ::: TOPIC .......
38: Tubes Asylum, Some Triplett 3444 observations - and a call for Michael Samra (0.00)
Posted by Legendre on 2011-05-20, 10:07:11 (76.17.236.110)
I've been doing quite a bit of work with the Triplett 3444 testers recently, and came across something that strikes me as odd. An interesting feature of these testers is found in the function of the L .......
39: Tubes Asylum, RE: This would be the place, (0.00)
Posted by Legendre on 2011-05-09, 11:17:44 (71.195.16.225)
Pardon my thread necromancy.. I'm not sure that I ever managed to contact Michael to obtain the 3444 document he offered. It's not in my files, anyway. How do I contact him? I don't see any "contact m .......
40: Tubes Asylum, RE: This would be the place, (0.00)
Posted by Legendre on 2010-08-12, 23:57:51 (71.195.16.225)
Thanks for the reply Cory. I sort of figured that if anyone on AA were in a position to help, they'd eventually show up. On this end, progress continues and a couple of issues have been solved - impo .......
41: Tubes Asylum, Is there a better place to post this? (NT) (0.00)
Posted by Legendre on 2010-08-11, 21:13:01 (71.195.16.225)
This space intentionally left blank. .......
42: Tubes Asylum, Need help with Triplett 3444 tester repair / cal (0.00)
Posted by Legendre on 2010-08-11, 10:57:28 (71.195.16.225)
I'm currently bringing back a late (10K serial #) Triplett 3444 and I've run into a strange problem. FYI, all electrolytics and old SS rectifiers have been replaced. Here's the deal: One of the first .......
43: OTL Asylum, RE: Atma-sphere MP-3 or Aesthetix Calypso (0.00)
Posted by Legendre on 2010-06-20, 21:24:11 (24.131.135.40)
While it's not super common, used MP-3 do show up for sale. If you're considering buying a used MP-3, make sure that the seller clearly discloses any updates / upgrades that have been performed on th .......
44: OTL Asylum, RE: GM20 questions (0.00)
Posted by Legendre on 2010-06-08, 18:22:48 (24.131.135.40)
The schematic is clearly wrong wrt the EF184 tube(s), as least as far as the labeling is concerned. Grid 1 (control) is mislabeled as 'G2'. To confound matters further, when we see the odd connection .......
45: OTL Asylum, RE: GM20 questions (0.00)
Posted by Legendre on 2010-06-08, 09:35:14 (24.131.135.40)
Have you given any thought as to the possible location of the MV1 device? If I had to guess, I'd say it was thermally coupled to the output tubes.. to act as a temperature-dependent bias current regul .......
46: Vinyl Asylum, Yes it was bent, and here's what we did to fix it.. (0.00)
Posted by Legendre on 2010-06-07, 17:01:36 (24.131.135.40)
Ok, thanks to all. Yes, it was most definitely bent - the bend was in both the X and Z axes (it appeared bent from directly above as well as from the side). So here's what we did with it: Removed the .......
47: Vinyl Asylum, Quick Dual 1229 question (0.00)
Posted by Legendre on 2010-06-07, 09:36:15 (24.131.135.40)
Should the tonearm on the Dual 1229 have a slight but obvious curvature - or should it be perfectly straight? I have one here with a curve in the tonearm tube - and I'm not sure if I should straighten .......
48: OTL Asylum, RE: The notes about the wiring (0.00)
Posted by Legendre on 2009-07-03, 22:05:48 (66.41.159.76)
If you are simply bi-wiring, the provided Cardas posts should have sufficient throw to easily accept two lugs per terminal. If you'd like to drive powered subs with the voltage signal from the output, .......
49: OTL Asylum, RE: I am new here... (0.00)
Posted by Legendre on 2009-07-02, 19:15:35 (66.41.159.76)
You'll need to take a look at it, but you might be able to add a second set by using the existing (two) holes as provisions for two new pairs of posts.. i.e. you punch two holes, one each (respectivel .......
50: OTL Asylum, http://www.twitter.com/Atma_Sphere (0.00)
Posted by Legendre on 2009-07-02, 18:51:08 (66.41.159.76)
What the hell, why not? I'm sure it's a CIA front.. but hey, you gotta feed the machine once in a while. -L .......
51: OTL Asylum, The Slovak republic was never Russia (0.00)
Posted by Legendre on 2008-09-07, 07:19:08 (66.41.159.76)
All, JJ tubes are manufactured in the Slovak Republic, a state which (as the Slovak Socialist Republic) was part of Czechoslovakia until 1993: http://en.wikipedia.org/wiki/Czechoslovakia While a form .......
52: OTL Asylum, RE: fourier panther mark 2 amps (0.00)
Posted by Legendre on 2008-09-07, 06:59:35 (66.41.159.76)
Howdy RnH, As you might (or might not) have gleaned from previous discussions, the tube sockets themselves are a common point of failure on any 6C33-based amplifier; Fourier or otherwise. In particula .......
53: OTL Asylum, RE: Zu Druids in MN (0.00)
Posted by Legendre on 2008-07-01, 18:43:10 (24.118.132.50)
Hi Duke, Yes, we have a pair of Druids. -Bill .......
54: OTL Asylum, RE: Mogami Neglex XLR (0.00)
Posted by Legendre on 2008-03-02, 07:00:10 (24.118.132.50)
Glad to hear that you're willing to give the Mogami a try. Do the specifications on these $56 cables mention the wire type? There are two types which are considered suitable for balanced audio IC: Typ .......
55: OTL Asylum, RE: Went Back to M60ll Stock input Setup.1mf caps (0.00)
Posted by Legendre on 2008-02-25, 19:10:07 (24.118.132.50)
I've parsed (with some difficulty) that tubevib was running 3.3uF coupling caps in tis M-60 amps. Obviously, the stock value is 0.10uF, with a maximum of 0.22uF allowable in this position. I'd need to .......
56: OTL Asylum, RE: BEAST by TRANSCENDENT (0.00)
Posted by Legendre on 2008-02-24, 16:28:56 (24.118.132.50)
Hi horn150, You might already know this, but Bruce Rozenblitt maintains a user forum over at the Transcendent Sound website. Last time I looked, it was mostly DIY related questions. But as a general s .......
57: OTL Asylum, RE: Looking for Ralph (0.00)
Posted by Legendre on 2008-02-24, 16:15:45 (24.118.132.50)
I'm not sure why the Rendition email isn't working.. you can try him at his Atma-Sphere address - ralph at atma-sphere dotcom. Fwiw, he shipped a refurbished demo Evo One amp on Friday of last week; I .......
58: OTL Asylum, RE: Does Anyone Know this Amp (0.00)
Posted by Legendre on 2008-02-05, 16:13:19 (24.118.132.50)
I'm dubious that these amps were made in 1960.. those green conformal coated boards for one, and many of the parts are later (like the Cardas jacks / posts). Of course, it could have been heavily rewo .......
59: OTL Asylum, 6080 / 6AS7 vs. 6AS7G (0.00)
Posted by Legendre on 2008-02-05, 06:12:48 (24.118.132.50)
Wanted to point out that the 6080 is a ruggedized military / industrial version of the 6AS7; not the 6AS7 G . The 'big bottle' (ST16) 6AS7G types have large heat radiating fins atop the grid structur .......
60: Dynaco-Doctor Forum, RE: The ST-70 issue (0.00)
Posted by Legendre on 2008-01-23, 16:35:20 (66.41.18.84)
Hello Cyril, As Bob suggests, you simply have a bad power switch on the ST-70. No great shakes, there. The PAS is another matter entirely. When it comes to fixing these things, it's all a matter of ho .......
61: Dynaco-Doctor Forum, RE: sds capacitor repacement board for sca35 (0.00)
Posted by Legendre on 2008-01-21, 06:51:48 (66.41.18.84)
They should connect to the K1 and K2 points on the board, or directly to the (common) cathode connection of either pair of output tubes, whichever is more convenient. Just be sure to connect the pot .......
62: Dynaco-Doctor Forum, Two questions (0.00)
Posted by Legendre on 2008-01-21, 06:20:05 (66.41.18.84)
1) You mentioned that it has a new power transformer; what is the B+ voltage in this amp? (measured with a full set of tubes, biased up) 2) What brand of output tubes are you using? I don't do a lot .......
63: Dynaco-Doctor Forum, RE: ST70 S7P problem (0.00)
Posted by Legendre on 2008-01-19, 14:37:51 (66.41.18.84)
Check to make sure that the Plate regulator is running properly, and that the full plate voltage output (as read on the reg. board) is appearing at the plate terminals of all tubes.. if the plate supp .......
64: OTL Asylum, RE: Thanks...definitely helps! (0.00)
Posted by Legendre on 2008-01-16, 11:11:44 (71.34.57.94)
Correct, followed by V4 and finally V3. .......
65: OTL Asylum, Correction (0.00)
Posted by Legendre on 2008-01-16, 10:28:39 (71.34.57.94)
Arrgh.. hate it when I do that.. I gave you the order in reverse. I went back and corrected my original post to read "from the output tube side". The term 'driver' is fairly vague; in many instances, .......
66: OTL Asylum, RE: MA1 MkII.3 Input Tube Positions (0.00)
Posted by Legendre on 2008-01-16, 05:24:11 (71.34.57.94)
Hi Jordan, For any 5-tube Mk.II style (long chassis) MA-1, starting from the output tube side: V4 - output section driver V2 - top of cascode voltage amplifier V1b / V1a - bottom of cascode voltage am .......
67: OTL Asylum, Followup (0.00)
Posted by Legendre on 2008-01-11, 06:56:11 (66.41.18.84)
Took a look in the Sylvania manual, and I see there is an example OTL circuit for this tube. The example depicts two tubes in an SEPP arrangement driving loads from 250 - 800ohms producing 4-5W max. : .......
68: OTL Asylum, RE: 7695 OTL tube (0.00)
Posted by Legendre on 2008-01-09, 15:18:25 (71.34.57.94)
I think you're confusing the suggested cathode bias resistor (Rk) with the plate resistance. My RCA manual lists 200ohms as well - but it's for the Rk. .......
69: OTL Asylum, RE: Atma-Sphere M60 MK3 (0.00)
Posted by Legendre on 2008-01-09, 06:27:54 (66.41.18.84)
"I found the autoformers work as advertised. While they do not entirely escape having a sonic signature (what does?), using them when needed typically tips the tradeoff in their favor." This is precis .......
70: OTL Asylum, RE: 7695 OTL tube (0.00)
Posted by Legendre on 2008-01-08, 18:09:16 (66.41.18.84)
If you're talking about the 7695 industrial type, it's a beam power tube. 50V @ 150mA heater, 7000ohm Rp, 4.5W power into 1100ohms for a single tube (class-A). We must be talking about different devic .......
71: OTL Asylum, RE: Dear LAN (0.00)
Posted by Legendre on 2008-01-03, 16:12:36 (66.41.18.84)
Pretty sweet set of electronics there.. plus, they're their own stands! Gotta love it. .......
72: OTL Asylum, RE: I see dead foaks, 08 an the Circlotron is King......! (0.00)
Posted by Legendre on 2008-01-02, 19:45:29 (66.41.18.84)
Hi Tubevibb, As for OTLs, I'm pretty happy with the Circlotron topology for '08 and beyond! .......
73: OTL Asylum, RE: OT .......... Would the triodes .......... (0.00)
Posted by Legendre on 2008-01-02, 16:32:04 (66.41.18.84)
6SN7 (small-signal driver) are suitable to just about any conventional design.. but perhaps you were referring to the 6AS7 dual power triode (output tube)? In that case - absolutely.. the low plate re .......
74: OTL Asylum, RE: Web site down? (0.00)
Posted by Legendre on 2008-01-02, 16:17:41 (66.41.18.84)
Hi Duane, There was a hiccup in our connection this morning and early afternoon, but as of this writing, things are restored. If there are any pending emails, wait a few days before re-sending if you .......
75: General Asylum, Who are the men in this photo? (0.00)
Posted by Legendre on 2007-12-31, 16:09:13 (66.41.18.84)
Sorry, this is a bit of a cross post from the general Music asylum.. This is one of a series of three photos, from a jazz recording session sometime in the late 1950s or early 1960s. Trouble is, I .......
76: Music Lane, Can anyone peg down the year? (0.00)
Posted by Legendre on 2007-12-31, 16:02:55 (66.41.18.84)
From what I can gather from styles, these photos were taken sometime between 1958 and 1964.. anyone care to hazard a closer guess? Btw, I might make a wee cross-post to the main forum, see if it gathe .......
77: Music Lane, RE: Who is in these (jazz) session photos? (0.00)
Posted by Legendre on 2007-12-31, 10:55:01 (63.224.21.219)
No idea where or when these photos were taken. They are in the form of 8-1/2" x 11" glossy prints, but they don't seem to be on photo stock. I think they're litho or half-tone repros of the original p .......
78: Music Lane, RE: I'm guessing here (0.00)
Posted by Legendre on 2007-12-31, 05:32:20 (66.41.18.84)
Hi Stu, What a thought.. thing is, was Previn ever known as a Hammond player? I only know of him as a pianist. Otherwise, there are a few visual similarities to early photos of Previn, though the hai .......
79: Music Lane, Shelly Manne? (0.00)
Posted by Legendre on 2007-12-31, 05:16:50 (66.41.18.84)
Hm, very interesting guess.. here's a link to a page with a number of photos of Manne: Shelly Manne at Drummerworld Right hairstyle, color, head shape and playing a similar kit in several photos. I th .......
80: Music Lane, Who is in these session photos? (0.00)
Posted by Legendre on 2007-12-30, 17:28:21 (66.41.18.84)
I found these three photos around five years ago. They seem to be of a jazz recording session, sometime in the mid 1960's or earlier.. based on the style of dress and the Ampex 350 series tape equi .......
81: Dynaco-Doctor Forum, RE: Hey Joe - Balanced inputs for the ST-70? (0.00)
Posted by Legendre on 2007-10-23, 06:16:00 (66.41.18.84)
Thanks for the info, sounds good. This kid isn't going to know how to act, when his ST-70 comes back with XLR inputs ;-) I'll order one up later this week. -Bill .......
82: Dynaco-Doctor Forum, Hey Joe - Balanced inputs for the ST-70? (0.00)
Posted by Legendre on 2007-10-19, 13:26:37 (63.224.21.219)
Hi Joe / All, I noticed that your CCDA premium modification has a differential amp at the input, though it's clearly wired up for SE input in the schematic. Have you ever tried setting this up for a t .......
83: Vinyl Asylum, Kind of confirms my belief (0.00)
Posted by Legendre on 2007-01-06, 04:57:15 (66.41.18.84)
My guess is that they didn't think they'd get another take like that one (and what a performance it is) and just went with the slightly flawed recording. Unless she was actually overloading the mic, t .......
84: Vinyl Asylum, Re: The Turntable Packing Wall of Shame (0.00)
Posted by Legendre on 2007-01-06, 04:37:54 (66.41.18.84)
Sad part is, sometimes even the well packed tables don't make it. I kind of pride myself on the ability to pack fragile equipment - my only defeat was a near mint Thorens 125 that the USPS quite liter .......
85: Vinyl Asylum, Re: I don't think that's reissued on cd- (0.00)
Posted by Legendre on 2007-01-05, 17:31:49 (66.41.18.84)
Thanks Mike. Terre (oops) has an astonishing, powerful voice, very obvious on that record. It's one of my all-time favorites.. good thing it's common and cheap ;-) .......
86: Vinyl Asylum, Question - Roches Seductive Reasoning (0.00)
Posted by Legendre on 2007-01-05, 15:32:37 (66.41.18.84)
Hopefully, someone will be familiar enough with this record, to know the answer to this question. Track 3, side 1 - "West Virginia".. This is a rather quiet track, with the exception of two (possibly .......
87: OTL Asylum, Holiday Greetings and a Happy New Year to all (0.00)
Posted by Legendre on 2006-12-18, 16:12:17 (66.41.18.84)
I've been a little bit scarce around here, so thought I'd get this out before it's too late! Just wanted to extend my best wishes for a Happy Holiday, and a peaceful and prosperous New Year to everyon .......
88: OTL Asylum, Re: Ralph, check this out. (0.00)
Posted by Legendre on 2006-12-18, 15:39:28 (66.41.18.84)
That's a lot of TT for $291.00. Nice to see that they are holding their average value.. neither crashing down nor heading for the stars. .......
89: OTL Asylum, Re: My error on use of AW Super Regulator in preamp (0.00)
Posted by Legendre on 2006-12-18, 15:35:19 (66.41.18.84)
Lew, I'd just like to understand how it manages to work with an HV transformer with only a single output winding - center tapped, or not. While it's up on the bench, would you mind indulging me with a .......
90: OTL Asylum, Re: Which is most sonically critical 6SN7 - Atma MP3/M60? (0.00)
Posted by Legendre on 2006-12-15, 20:59:04 (66.41.18.84)
jb, It's an interesting question. The 6SN7s in the MP-3 are doing very different service than those in the V1 & V2 positions of the M-60. In the MP-3, the dual sections of a single 6SN7 serve as the a .......
91: OTL Asylum, Re: That WAS a dumb question! :-{ (0.00)
Posted by Legendre on 2006-11-22, 12:04:48 (66.41.8.98)
"Does Radio Shack even sell electronics parts these days?" Just a few odds & ends, and most of it is overpriced and low-quality. .......
92: OTL Asylum, Re: Split rail regulated power supply (0.00)
Posted by Legendre on 2006-11-09, 16:29:21 (66.41.8.98)
Lew, "What have I got wrong?" You might not have anything wrong, Lew - I may just be ill-informed as to the behavior of the SuperReg. I was under the impression that the HV portion of the SuperReg ess .......
93: OTL Asylum, Re: Split rail regulated power supply (0.00)
Posted by Legendre on 2006-11-09, 06:41:36 (66.41.8.98)
You can only use a center tapped secondary & single bridge, if the regulators are simple shunts like zeners or gas tubes. Devices like the SuperReg cannot be used in this fashion. If you're curious wh .......
94: OTL Asylum, Re: Split rail regulated power supply (0.00)
Posted by Legendre on 2006-11-06, 16:20:35 (66.41.8.98)
Doug, In this case, I assume that by 'shunt regulator' you mean Alan's SuperReg. Yes, you can 'stack' them, to create your +/- regulated supply. The right way to do this, is to use an HV transformer w .......
95: OTL Asylum, Re: MP-3 line input (XLR) sensitivity (0.00)
Posted by Legendre on 2006-11-01, 16:16:03 (66.41.8.98)
Stephane, Since the volume control on the MP-3 comes before the linestage electronics, you can't saturate the input with too large of a signal. However, you might find that with the 6V setting, you do .......
96: OTL Asylum, Modding the MP-1? (0.00)
Posted by Legendre on 2006-10-31, 06:04:47 (66.41.8.98)
Hi Lew.. so what are you up to with the MP-1? .......
97: OTL Asylum, Re: Not recommended (0.00)
Posted by Legendre on 2006-10-25, 06:26:57 (66.41.8.98)
Careful with those. I've heard that In Soviet Russia, the capacitor rolls YOU! .......
98: OTL Asylum, Re: Not recommended (0.00)
Posted by Legendre on 2006-10-24, 17:23:58 (66.41.8.98)
Lew is correct - 200V isn't high enough. The steady-state plate voltage is usually a bit less than 200V, but the caps will see +325 at turn on, until the heaters have come up. Don't do it. If these ca .......
99: OTL Asylum, Re: 200 parts is a minimum ! (0.00)
Posted by Legendre on 2006-10-21, 15:19:48 (66.41.8.98)
How do those USA made 6AS7 / 6080 types hold up in your equipment? .......
100: OTL Asylum, Re: Thanks Bill (0.00)
Posted by Legendre on 2006-10-19, 16:34:29 (66.41.8.98)
CCM, I made a typo in my previous post - the suffixes are in alphabetical order, in terms of supposed increasing quality; -J, -Q, -T. The information about the higher-spec suffixes came to me just yes .......
101: OTL Asylum, Re: Interested in buying bulk 6AS7's (0.00)
Posted by Legendre on 2006-10-18, 18:02:36 (66.41.8.98)
The common Russian-made 6AS7G variant is a 6N13S - which looks like 6H13C in cyrillic text. These tubes were produced variously at the Svetlana (St. Petersburg), Reflector (Saratov)and Ulyanov plants. .......
102: Tube DIY Asylum, Re: Opinions needed - building a 12V 'convertor' (0.00)
Posted by Legendre on 2006-10-15, 07:46:10 (66.41.8.98)
Yes, this will work just fine. However, if the original circuit requires that the filament supply be somehow referenced to ground / HV, you'll have to do the same for the new 12V supply. .......
103: OTL Asylum, Re: addendum (0.00)
Posted by Legendre on 2006-10-10, 17:04:21 (66.41.8.98)
Tomahawk, Lew, The S-30 already has HexFred devices in the high-voltage supplies; shouldn't be much need to tinker with those. However, the four circlotron supplies do use standard hole-mounted bridge .......
104: OTL Asylum, Re: 6c33c sockets (0.00)
Posted by Legendre on 2006-09-29, 07:08:37 (66.41.8.98)
Rob, Interesting, I've never seen that type of socket for the 6C33C. They do look like quality parts, though. The price seems fair, I'd give them a try. .......
105: OTL Asylum, Re: 6c33c sockets (0.00)
Posted by Legendre on 2006-09-28, 16:18:24 (66.41.8.98)
Rob, The only Russian 6C33C sockets I have ever seen are white ceramic with silver plated contacts.. never came across any brown (mica?) parts. In the older days, each 6C33C shipped with one of these .......
106: OTL Asylum, Re: power trannies for m-50's (0.00)
Posted by Legendre on 2006-09-26, 08:44:25 (66.41.8.98)
Hi Cbird, I don't recognise the part number - is this the filament / HV transformer, or the B+? The Subtronics (just like the Talema and Avel Lindberg) transformers were custom made for Atma-Sphere. I .......
107: OTL Asylum, Re: Futterman H3 Blowing Fuse (0.00)
Posted by Legendre on 2006-09-26, 08:17:45 (66.41.8.98)
What are you on about now, tubevib? An autoformer has nothing to do with this issue... And what's preventing you form registering a nickname / moniker? :-) .......
108: OTL Asylum, Re: Z-Audo-former where are thay? (0.00)
Posted by Legendre on 2006-09-26, 08:15:00 (66.41.8.98)
The Z-Music transformer hasn't been built or offered in many years.. Paul Speltz' ZERO Autoformer serves the same purpose, nicely. .......
109: Amp/Preamp Asylum, Re: Interesting... (0.00)
Posted by Legendre on 2006-09-21, 18:56:50 (66.41.8.98)
Delaney wrote: "I also wonder if the Atma-Sphere folks ever worked for or with Audio Research... being from the same city...." It does seem likely, but in fact, there has never been any exchange of pe .......
110: OTL Asylum, Output B+ voltages (0.00)
Posted by Legendre on 2006-09-21, 07:22:35 (66.41.8.98)
In an M-60, the no-load voltage of the output B+ supplies is around 155V. Under full load (amp warmed up, and fully biased) it should settle at about 138V. .......
111: OTL Asylum, Notes on fixed bias operation (0.00)
Posted by Legendre on 2006-09-21, 07:12:56 (66.41.8.98)
The fixed bias is a convenience measure, and has proved to be very popular. Even though setting bias on an Atma-Sphere amp is quite trivial, when someone sees a chassis with 8, 14 or 20 power tubes, a .......
112: OTL Asylum, Re: Bias Potentiometer resistance path (0.00)
Posted by Legendre on 2006-09-20, 04:39:51 (66.41.8.98)
Stu (and others), The fixed resistor is not strapped across the pot, it's in series with it (to ground). The reason for the resistor should be fairly obvious - it limits the range of the bias control .......
113: OTL Asylum, Re: Power Calculations - No Clipping (0.00)
Posted by Legendre on 2006-09-20, 04:17:04 (66.41.8.98)
Stu, Based on what I read, your methods seem to be correct.. unfortunately, Ralph is out of town at the moment, and I can't compare notes with him. One other thing to look at: are you keeping the line .......
114: Tweakers' Asylum, Re: The wow is pronounced even on the Pabst.... (0.00)
Posted by Legendre on 2006-09-19, 15:42:26 (66.41.8.98)
If you're interested, I have a source for the caps.. The original is 4uf +/- 10% (so 3.6 - 4.4uF), and the replacements are 4.4uF. Same size can and general layout, tho; fits very well. .......
115: Vinyl Asylum, Yes. (0.00)
Posted by Legendre on 2006-09-19, 08:14:51 (66.41.8.98)
Yes, I have a source for these. Sent you a mail via the A^2 'mail an inmate' feature. .......
116: Tweakers' Asylum, Papst (0.00)
Posted by Legendre on 2006-09-19, 07:56:08 (66.41.8.98)
Unless you're working with a Blue Ribbon motor ;-) .......
117: Vinyl Asylum, Re: Empire turntable (0.00)
Posted by Legendre on 2006-09-18, 20:22:03 (66.41.8.98)
I'm working with several of these tables right now. The spring only needs to be strong enough to positively return the motor to the fully out position, if you pull it inward - then release it. It's a .......
118: Vinyl Asylum, Re: Are they RCA pressings with a circular RCA logo? (0.00)
Posted by Legendre on 2006-09-18, 20:06:06 (66.41.8.98)
Nope, no indication of RCA anywhere. They are fairly plain labels, one yellow, the other dark blue. All they say are "Collector's", and in another area "Limited edition". They seem to be part of a ser .......
119: Tube DIY Asylum, Re: which way for polypropylene capacitor (0.00)
Posted by Legendre on 2006-09-18, 16:50:18 (66.41.8.98)
On a film cap, there are no 'polarity' issues, but there are some general rules of thumb for application: - If the cap has a band on it, the band goes to the lower potential side of the circuit (to gr .......
120: OTL Asylum, Re: Power Calculations - No Clipping (0.00)
Posted by Legendre on 2006-09-18, 16:37:34 (66.41.8.98)
Stu, First, you need to be sure that neither the signal generator nor the oscilloscope are tied to ground. These are true balanced amps, and if any of the input or output terminals are tied to ground, .......
121: Vinyl Asylum, Fats Waller - Organ vols 1 & 2 180g (0.00)
Posted by Legendre on 2006-09-18, 15:56:31 (66.41.8.98)
Anyone know about these discs? Fats Waller - Organ, volume 1 & 2 (12" LP, mono, looks like microgroove for playback on stereo tables). Part of a "collectors's edition" series, they come in light paper .......
122: Tube DIY Asylum, Re: Cardas RCA jacks: do their ground collars solder? (0.00)
Posted by Legendre on 2006-09-12, 06:52:44 (66.41.8.98)
We solder to the body of the Rhodium Cardas RCA jacks everyday, using a 48W Weller WTCP type solder station, set at 700F. Solder can be basic SN63/PB37 with a P2 or P3 flux; I've never tried 60/40. Pr .......
123: Tube DIY Asylum, Re: does anyone know about this tube tester? (0.00)
Posted by Legendre on 2006-09-12, 06:29:11 (66.41.8.98)
Greetings Mike, long time no talk.. I've never had my hands on one, but it seems to be similar to the Sofia curve tracer, but without the required link to the PC. This makes sense, as compute power ha .......
124: Dynaco-Doctor Forum, Re: Can't get it up (0.00)
Posted by Legendre on 2006-08-23, 07:36:56 (66.41.8.98)
More than likely, it's one of two things: 1) Plate / screen voltages too low 2) Bias voltage too negative Take measurements with a full set of tubes, and give the amp some time to warm up first. ::: T .......
125: Amp/Preamp Asylum, Your grounding setup (0.00)
Posted by Legendre on 2006-08-23, 07:27:00 (66.41.8.98)
How is this table grounded? The comment about "multiple ground wires" is of some concern - normally, having more than one ground wire will cause more trouble than it fixes. So, how many grounds do you .......
126: General Asylum, Re: MP3 - A Little Information Please (0.00)
Posted by Legendre on 2006-08-23, 07:10:39 (66.41.8.98)
Man, you must be *really* lazy... ;-) http://en.wikipedia.org/wiki/MP3 MP3 is short for "MPEG-1 Layer-3". Essentially, an MP3 is the compressed audio track format used in MPEG-1 audio / video programs .......
127: Amp/Preamp Asylum, Re: Look to partner a tube pre with a transistor or Class D power amp. What are the obvious pitfalls? (0.00)
Posted by Legendre on 2006-08-19, 06:49:44 (66.41.8.98)
The main issue with driving SS gear from a tube preamp, is that tube preamps tend to have high-ish output impedances, while SS gear tends to have low-ish input impedances. While these are just the bas .......
128: Tube DIY Asylum, Re: ENIAC is digital.. and 100% valve.. no op amps.. (0.00)
Posted by Legendre on 2006-08-17, 07:07:47 (66.41.8.98)
Keep in mind that the first op-amps were built from valves.. By no means are 'op-amp' and 'valve' mutually exclusive. .......
129: Tube DIY Asylum, Re: What soldering iron? (0.00)
Posted by Legendre on 2006-08-17, 06:52:32 (66.41.8.98)
If you're doing general electronic service, that iron is more than sufficient. I'm not familiar with the Wintal brand, but it *looks* like it's designed for professional use. I'm fond of the Weller WT .......
130: Dynaco-Doctor Forum, Re: effect of lower or higher bias points on MKIV (0.00)
Posted by Legendre on 2006-08-16, 07:42:14 (66.41.8.98)
First and foremost, running the amp with higher-than-specified bias will shorten the life of both the output tubes and the rectifier tube (if it still has the tube rectifier). It will also add strain .......
131: OTL Asylum, Chiming in... (0.00)
Posted by Legendre on 2006-08-13, 07:45:02 (66.41.8.98)
The leakage RK mentioned is heater-cathode leakage, which is fairly typical in the Russian 6SN7 types. Since the filaments are AC, any leakage will superimpose a 60Hz AC signal onto the cathode, which .......
132: OTL Asylum, Re: Novacrons - Legendre's April Thread (0.00)
Posted by Legendre on 2006-08-13, 07:18:57 (66.41.8.98)
Dennis, Thanks for all the kind words, and I'm delighted to hear that you've enjoyed owning the Novacron pair. Part of the credit for the reliable performance goes to Otto at New Sensor (NYC), who sup .......
133: OTL Asylum, Re: Theory behind OTL (0.00)
Posted by Legendre on 2006-08-02, 07:45:12 (66.41.8.98)
While this is a broad generalization, there are two basic subclasses of practical OTL tube amplifier: AC coupled and DC coupled. The DC types generally fall into one of two topologies: Circlotron and .......
134: Amp/Preamp Asylum, Re: RCAs will not release!! Suggestions PLEASE!? (0.00)
Posted by Legendre on 2006-08-02, 07:07:43 (66.41.8.98)
If they are really stuck hard - and I had to make a guess - I'd say that the issue was due to dissimilar metal (galvanic) corrosion. Even if the connectors are (were) plated in precious metal, all it .......
135: Vintage Asylum, It was just cancelled by Ebay /nt (0.00)
Posted by Legendre on 2006-07-23, 11:13:38 (66.41.8.98)
.......
136: OTL Asylum, Re: Atma-Sphere M60 MK2.III hum and noise question (0.00)
Posted by Legendre on 2006-07-23, 08:11:17 (66.41.8.98)
I'm a little unclear on this: Without anything connect to the speaker except for the amp Do you normally have something connected to the speaker, in addition to the amp? Or did you mean "Without anyth .......
137: General Asylum, Armor-All? Not with a 10-foot pole.. (0.00)
Posted by Legendre on 2006-07-21, 17:00:52 (66.41.8.98)
Do not use Armor-All.. It will look great for a short time, and then it will rot to pieces. As a motorcycle mechanic, I have seen Armor-All completely ruin good rubber (new tires even) and vinyl more .......
138: Tube DIY Asylum, Re: weird 12ax7 class a cct (0.00)
Posted by Legendre on 2006-07-20, 06:39:23 (66.41.8.98)
Actually, automotive coils were nothing but a step-up transformer, that charged the condenser (some people call them capacitors Ignition coils are step-up transformers, but their job is firing the sp .......
139: Amp/Preamp Asylum, Re: Differences between Class A and A/B amplifier? (0.00)
Posted by Legendre on 2006-07-19, 16:43:37 (66.41.8.98)
Think of it like this.. Given two amplifiers, of identical construction - but one biased for Class-A and the other biased for Class-AB: The Class-A amp will (generally) tend to have better sonics, whi .......
140: General Asylum, There is a 'truthiness' to it.. (0.00)
Posted by Legendre on 2006-07-19, 16:26:07 (66.41.8.98)
On many levels, the old chestnut "bits are bits" is a 100% true statement. Doesn't matter if these bits are in RAM, on a hard disk, on optical media (CD) or printed on a piece of paper - as long as th .......
141: Tube DIY Asylum, That's amusing *and* dangerous (0.00)
Posted by Legendre on 2006-07-19, 06:28:20 (66.41.8.98)
Heh, don't touch the speaker terminals.. .......
142: OTL Asylum, Make that DC balance (offset) and bias /nt (0.00)
Posted by Legendre on 2006-07-17, 05:21:26 (66.41.8.98)
.......
143: General Asylum, China (fake Rubycon caps) (0.00)
Posted by Legendre on 2006-07-17, 05:18:48 (66.41.8.98)
(posted this in tube-DIY a while back, but it seems relevant) Recently, a friend purchased a small lot of supposedly new, genuine Rubycon electrolytics from a Chinese vendor. You guessed it, they were .......
144: Dynaco-Doctor Forum, Re: New stock PAS board (0.00)
Posted by Legendre on 2006-07-14, 15:59:01 (66.41.8.98)
Bob, Consider finding yourself a nice pair of smooth-plate Telefunken 12AX7 for the PAS phonostage. They will probably cost dearly, but they will sound superb in there, and they will last for just abo .......
145: Vintage Asylum, Re: FM3 Alignment (0.00)
Posted by Legendre on 2006-07-13, 06:38:35 (66.41.8.98)
The FM-3 alignment procedure in the Dyna manual is quite explicit and very effective. If you can follow directions, you can align the tuner. After you replace the quad cap, why not do a practice align .......
146: Tube DIY Asylum, No, values run as high as 30Meg (0.00)
Posted by Legendre on 2006-07-13, 06:23:00 (66.41.8.98)
You must be looking at one of the other Caddock lines.. they make a lot of different parts. Again - The Caddock MS series are standard axial leaded parts, with a range of values to 30M and power to 22 .......
147: Tube DIY Asylum, parallel resistors (0.00)
Posted by Legendre on 2006-07-13, 06:15:38 (66.41.8.98)
Paralleling resistors for sonic advantage is nothing new - in general, lowering the current density in a resistor lowers the noise, and paralleling parts is one means to this end. Simply using higher .......
148: Tube DIY Asylum, Caddock (0.00)
Posted by Legendre on 2006-07-12, 06:07:36 (66.41.8.98)
Caddock MS series - power to 22W, values from 20R to 30M. You can probably just use a single 22W 75K device for your application. .......
149: Dynaco-Doctor Forum, That just doesn't work (0.00)
Posted by Legendre on 2006-07-12, 05:20:17 (66.41.8.98)
Critical issue: If your power transformer has only ONE 5V filament winding for the rectifier(s), it is impossible to create a "PDMPS" from it. The 5AR4/GZ34 rectifier has its cathode tied internally t .......
150: Dynaco-Doctor Forum, Re: found it 40/40/20/20 Where can I get this? (0.00)
Posted by Legendre on 2006-07-12, 04:32:40 (66.41.8.98)
CE Distributing makes this part - 40/40/20/20 @ 525V $33.95 from www.tubesandmore.com (Antique Electronic Supply). Doesn't Joe also sell these? .......
151: Dynaco-Doctor Forum, Re: Replacing transformer leads? (0.00)
Posted by Legendre on 2006-07-11, 17:38:26 (66.41.8.98)
James, If you pull the shells off of the core, you might find that the internal connections are accessible. Maybe a turn or two of paper has to come off, but that's easy enough to repair. Don't use an .......
152: Dynaco-Doctor Forum, Re: Stereo 70 issues (0.00)
Posted by Legendre on 2006-07-11, 04:57:23 (66.41.8.98)
I have just never seen a tube that works until it heats up then doesn't until it cools down a little (this seems odd to me) This isn't an everyday situation, but there is nothing really odd about it. .......
153: Vintage Asylum, Re: Thanks - question (0.00)
Posted by Legendre on 2006-07-10, 05:15:42 (66.41.8.98)
(chiming in...) Go to www.dynacodoctor.com (Joe Curcio's site) and download a copy of the FM-3 manual - and read it, cover to cover (you can probably skip over the assembly steps, for now). It contain .......
154: Dynaco-Doctor Forum, Oops, a correction (0.00)
Posted by Legendre on 2006-07-09, 16:20:28 (66.41.8.98)
The beam-forming plate is not the equivalent of the screen grid.. it's more like the equivalent of the supressor grid in a true pentode, though it functions differently. The screen grid in a beam powe .......
155: Dynaco-Doctor Forum, Re: Legendre (0.00)
Posted by Legendre on 2006-07-09, 08:35:25 (66.41.8.98)
Thing is, I don't really read a schematic, so I used the next project ST-70 (Ebay purchase) as a wiring guide. Kind of a cart-before-the-horse situation. Schematic reading (especially for these old t .......
156: Dynaco-Doctor Forum, That's not right (0.00)
Posted by Legendre on 2006-07-09, 07:26:14 (66.41.8.98)
You are reporting 424V on the (blank) quad section, and 422V on both pins 3 & 4 of the EL34 tubes. 424V is fine (it's within 3% of the 415 spec), but the fact that pins 3 & 4 have the *same* voltage i .......
157: Dynaco-Doctor Forum, Re: Glow on plates of EL34's (0.00)
Posted by Legendre on 2006-07-08, 08:22:46 (66.41.8.98)
Have you considered downloading a copy of the ST-70 manual from Joe's site? Since your unit is mostly stock, the checkout procedure should answer most if not all of the questions you raised. He also o .......
158: Dynaco-Doctor Forum, Re: Voltages normal but EL34 plates have slight glow... (0.00)
Posted by Legendre on 2006-07-06, 07:26:15 (66.41.8.98)
If the *rear* tubes are glowing, it sounds like the pairs are not well matched. Have you tried swapping the L front for the R rear? That would put both of the 'hot' tubes into one channel. Plate glow .......
159: Tube DIY Asylum, Re: Vibrating wirewound (0.00)
Posted by Legendre on 2006-06-29, 06:33:57 (66.41.8.98)
Are you sure that it's not just a sympathetic vibration - that is, the resistor is being excited by the (slight) vibration of the power transformer? If it's a leaded part, try adjusting its position s .......
160: Tube DIY Asylum, Good answer (0.00)
Posted by Legendre on 2006-06-26, 05:43:47 (66.41.8.98)
With many line-level sources (CD players, especially) producing enough output to easily drive a given amp to full power, there is little need for any pre-amplification in a 'linestage'. Aside from vol .......
161: Amp/Preamp Asylum, Re: comments on the new Krell EVO series? (0.00)
Posted by Legendre on 2006-06-24, 15:01:10 (66.41.8.98)
I'm wondering what BelCanto Design is thinking.. If Krell is using the 'Evo' name, that is bound to cause marketplace confusion. Or am I missing something, here? .......
162: General Asylum, Re: Ever been to Minneapolis-St. Paul (0.00)
Posted by Legendre on 2006-06-23, 21:11:29 (66.41.8.98)
Lived in the St. Paul / Mpls area all of my life.. and it's true, people here tend to be very friendly, and welcoming of strangers. Part of this comes from the hard winters.. only a fool makes enemies .......
163: Vintage Asylum, Can you elaborate on this? (0.00)
Posted by Legendre on 2006-06-22, 07:29:23 (66.41.8.98)
You lost me here, Mike.. I understand the concept of 110/115/125V primaries - but what accounts for the difference between two chassis? Are you saying that one was already rewired, but not the other? .......
164: Tube DIY Asylum, Negative Feedback /nt (0.00)
Posted by Legendre on 2006-06-20, 06:15:38 (66.41.8.98)
.......
165: Dynaco-Doctor Forum, The best advice I can offer (0.00)
Posted by Legendre on 2006-06-19, 06:44:50 (66.41.8.98)
Carl, Download a copy of the PAS-2/3 manual, and put the unit back to stock. Then, once it's working again, make one small incremental change at a time, checking your results with each small step. If .......
166: Tube DIY Asylum, Re: good heavens, no, i would never hack anything.... (0.00)
Posted by Legendre on 2006-06-19, 06:25:15 (66.41.8.98)
Charles, You have completely missed the entire point of my first reply.. no one is accusing you of anything, my friend. The point was not that you may have hacked another member's account; the entire .......
167: Tube DIY Asylum, Re: message to other member username RADIANCE.... (0.00)
Posted by Legendre on 2006-06-18, 14:30:08 (66.41.8.98)
Err.. unless you did some black-hat work, the only way you could have 'taken' someone else's moniker, would be if they had *failed to register* it. If it had been that important to them, they would ha .......
168: Tube DIY Asylum, Re: volume control value for a headphone amp (0.00)
Posted by Legendre on 2006-06-18, 09:17:08 (66.41.8.98)
No, that's not really true.. You can have just about any value attenuator at the input of a tube amp - so long as whatever source is connected (CD player, preamp etc) can drive that load. If you're pl .......
169: Vintage Asylum, You hit it squarely, Jim (0.00)
Posted by Legendre on 2006-06-18, 06:55:02 (66.41.8.98)
The military specified and optimized tube parameters for many different reasons - but "audiophile" quality sonics was not among them. If you find a good-sounding JAN tube, it's by coincidence, not des .......
170: General Asylum, More manufacturers than stores.. (0.00)
Posted by Legendre on 2006-06-18, 05:28:16 (66.41.8.98)
The Twin Cities is quite the little midwestern nexus of hi-fi hardware people. Here's a quick list off the top of my head, of the local businesses (not in any particuar order): - Tri-Planar (tonearms) .......
171: Tube DIY Asylum, Re: 300b fixed bias (0.00)
Posted by Legendre on 2006-06-16, 17:41:14 (66.41.8.98)
but where can i measure the bias? Is there a resistor in the cathode circuit? Measure it there, as a function of DC voltage drop across the resistor. .......
172: Tube DIY Asylum, Re: I've got this load of Vitamin Q's, (0.00)
Posted by Legendre on 2006-06-14, 15:26:19 (66.41.8.98)
If no other markings or codes are present, assume that signal travels the same direction as the printing. .......
173: Dynaco-Doctor Forum, Whoa, hold up a second then.. (0.00)
Posted by Legendre on 2006-06-10, 06:27:59 (66.41.8.98)
If the heater voltages are 'not even close' (what are they, btw?) that could easily be the reason that the main PSU voltages are running high. Heater voltage low, tube doesn't conduct as designed, fai .......
174: Dynaco-Doctor Forum, Voltages and more (0.00)
Posted by Legendre on 2006-06-09, 07:30:38 (66.41.8.98)
In light of the (rather pointless) mod that was done to the filament supply, I'd be suspicious that someone was also playing around with the main PSU. I don't have the manual handy, but if the voltage .......
175: Dynaco-Doctor Forum, Re: Just got my pas 3 (0.00)
Posted by Legendre on 2006-06-08, 17:07:45 (66.41.8.98)
The 'mystery' component in the filament supply is a bridge rectifier. 13V is just fine, for 12.6V nominal tubes. Unless the main power supply (quad cap, etc) has been rebuilt, I would do that *first* .......
176: Tube DIY Asylum, Re: replace a 5651 tube with a zener? (0.00)
Posted by Legendre on 2006-06-08, 16:58:29 (66.41.8.98)
My RCA tube manual lists the 5651A as being an ~85.5V reference, not 92V. This may be related to the A variant, but I'm too lazy to drag out the old books. Also, the 5651 isn't a VR tube per se, it's .......
177: Vintage Asylum, Thank you /nt (0.00)
Posted by Legendre on 2006-06-07, 19:09:50 (66.41.8.98)
.......
178: Tube DIY Asylum, You're making unwarranted assumptions (0.00)
Posted by Legendre on 2006-06-06, 10:21:56 (70.59.86.10)
Just because I show up to discuss Circlotron sections, doesn't mean that it's all about OTLs, or Atma-Sphere for that matter :-) I enjoy the hobby aspect as much as the next asylum inmate.. I'm not he .......
179: Tube DIY Asylum, No mystery here (0.00)
Posted by Legendre on 2006-06-06, 10:15:33 (70.59.86.10)
Did you bother to click that (M) next to my moniker? It spells out in plain English where I work. No mystery here. That's the whole point of the designation system - fair and open disclosure. You make .......
180: Dynaco-Doctor Forum, Re: How to extend transformer wires (0.00)
Posted by Legendre on 2006-06-05, 17:31:02 (66.41.8.98)
Well, you'll need to splice on some new lengths of wire. Just choose a quality wire of the same gauge and voltage rating (600V is best) - the new wire can be either be stranded or solid, since these p .......
181: Vintage Asylum, Need RCA WO-33A/B audio o-scope info (0.00)
Posted by Legendre on 2006-06-05, 17:05:11 (66.41.8.98)
Looking for documentation for the RCA WO-33A/B oscilloscopes.. kind of OT, but it seems like the kind of thing a vintage audio enthusiast might have laying around. These are the little 3" scopes which .......
182: Tube DIY Asylum, Re: Circlotron (0.00)
Posted by Legendre on 2006-06-05, 16:55:33 (66.41.8.98)
Has any inmate ever built or has experienced the sound of a circlotron amplifier? Sure, I build and use them all day long ;-) What would you like to know? (don't worry, no commercials here.. just fac .......
183: Tube DIY Asylum, Re: Ceramic sockets, a comment (0.00)
Posted by Legendre on 2006-06-05, 16:48:06 (66.41.8.98)
A well made ceramic does have a better (about 50% higher) dielectric strength as compared to a basic resin plastic like bakelite - however, mica has almost three times the strength of ceramic. I'm not .......
184: Tube DIY Asylum, Re: Ceramic sockets, a comment (0.00)
Posted by Legendre on 2006-06-05, 16:25:26 (66.41.8.98)
Couldn't have said it better myself. So, I wonder why people seem to prefer ceramic? Part of this is based on the idea that ceramic is more heat resistant, so that must be "better". Likewise, the chea .......
185: Dynaco-Doctor Forum, Re: Resistor Fun (0.00)
Posted by Legendre on 2006-06-05, 06:07:30 (66.41.8.98)
James, The Vishay/Dale (or the Draloric, Roderstein or RG Allen) parts would be a good choice. These are very similar to one another, and they are all neutral sounding metal film parts. Note also that .......
186: Tube DIY Asylum, Re: advantages of a B+ supply using ccS? (0.00)
Posted by Legendre on 2006-06-04, 08:18:13 (66.41.8.98)
It is an ambibuous question, so maybe I can help to narrow the field a bit. By CCS I assume you mean 'constant current source'.. by B+ I assume you mean the main power supply rail(s). In general terms .......
187: Tube DIY Asylum, oops!! (0.00)
Posted by Legendre on 2006-06-02, 17:09:10 (66.41.8.98)
I was confusing the old Pilot with a set of Ampex monoblocks which I owned around the same time. It was the Ampex which used the 6973, not the Pilot. My bad. .......
188: Vintage Asylum, Re: Vintage HH Scott SPL meter (0.00)
Posted by Legendre on 2006-06-02, 07:26:02 (66.41.8.98)
No, I didn't buy the meter on eBay - in fact, I didn't buy it at all. It belongs to a friend, who hordes all kinds of strange equipment. He actually had no idea what it was, or how it was used. I may .......
189: OTL Asylum, Thank you (0.00)
Posted by Legendre on 2006-06-02, 06:36:05 (66.41.8.98)
The apology is appreciated; wrong has been made right, and the matter is dealt with to our satisfaction. Respectfully request that this topic be considered closed. .......
190: Vintage Asylum, Vintage HH Scott SPL meter (0.00)
Posted by Legendre on 2006-06-01, 16:52:57 (66.41.8.98)
Came across an odd HH Scott SPL meter, looks to be from the early 1960s. Has a seperate power supply which connects to one end of the meter case, which looks like it was designed to accept either an A .......
191: OTL Asylum, Re: Transcendent SEOTL up and running.... (0.00)
Posted by Legendre on 2006-05-30, 20:58:32 (66.41.8.98)
Hey, that's cool.. From what I've read, the SEOTL seems like a pretty neat little amp. How long did it take to build the kit? The 6S19P is an interesting small power triode.. many desirable characteri .......
192: Vintage Asylum, Tuning Eye (0.00)
Posted by Legendre on 2006-05-30, 06:20:26 (66.41.8.98)
The green light from the tube is very dim, can only be visible at night with the ambient lights out. There might be more to this than meets the eye.. Ugh. The dim eye could mean that either the eye t .......
193: Tube DIY Asylum, Re: pilot c 1090 1958 console stereo (0.00)
Posted by Legendre on 2006-05-29, 15:25:43 (66.41.8.98)
It's a Pilot.. are you certain that it doesn't use 6973s? I know mine did.. .......
194: Dynaco-Doctor Forum, Re: per tube ST-70 bias with 4 15.6 ohm resistors (0.00)
Posted by Legendre on 2006-05-27, 17:09:21 (66.41.8.98)
Is my calculation correct here thinking that with the 15.6 ohm resistors I'll set my bias to .78 volts? Yes, you are correct. .78V across 15.6ohms = 50mA per tube (the specified bias current). Just r .......
195: Dynaco-Doctor Forum, Westinghouse? (0.00)
Posted by Legendre on 2006-05-27, 16:59:51 (66.41.8.98)
Just a guess - they look identical to the Westinghouse branded EL34/6CA7. .......
196: Vintage Asylum, suggested steps (0.00)
Posted by Legendre on 2006-05-27, 16:42:29 (66.41.8.98)
Flush your browser cache, saved passwords, saved form information, and so forth. Then restart the browser and try again. If you can't get in, there is a possibility that someone managed to get your pa .......
197: Tube DIY Asylum, Useful link re: vacuum tube regulators (0.00)
Posted by Legendre on 2006-05-27, 07:48:29 (66.41.8.98)
Here's a link to Steve's pages on vaccum tube voltage regulators; the information is generally quite good: http://members.aol.com/sbench/reg1.html Hope that helps. .......
198: Tube DIY Asylum, Common situation (0.00)
Posted by Legendre on 2006-05-26, 17:48:48 (66.41.8.98)
The EL84/6BQ5 is my favorite audio pentode in terms of musicality, and over the years I've owned many vintage amps which use this tube. In almost all cases, the power tubes were on their last legs whe .......
199: Dynaco-Doctor Forum, Re: My st70 stops humming when I take out rectifier tube? (0.00)
Posted by Legendre on 2006-05-25, 18:37:04 (66.41.8.98)
Removing the rectifier tube shuts down all of the DC power supplies in the amp, except for the bias supply. None of the tubes will amplify or even pass a signal, or noise. The filaments still run, of .......
200: Vinyl Asylum, Topic Records - Folk Music of Albania (0.00)
Posted by Legendre on 2006-05-25, 18:09:05 (66.41.8.98)
A friend came across this recording today, and it was a new one to me. Is this part of a series of world-folk records, along the lines of Nonesuch Explorer, and so forth? The quality of the recording .......
201: Dynaco-Doctor Forum, Re: What caps to order for my pas2? Help needed (0.00)
Posted by Legendre on 2006-05-25, 15:53:52 (66.41.8.98)
"Tubular" is what they used to call axial capacitors - one lead out each end. All coupling caps should be 600/630V. Anything higher just makes the parts larger and more costly, for no good reason. Act .......
202: Amp/Preamp Asylum, Re: It is certain that (0.00)
Posted by Legendre on 2006-05-25, 08:12:46 (66.41.8.98)
You make the point very well.. And in retrospect, my choice of words (well, one word) could have been better; "prices begin to exceed the $2000 range rather quickly" would have been more appropriate. .......
203: Amp/Preamp Asylum, Re: A bill of material does not a product make (0.00)
Posted by Legendre on 2006-05-25, 07:45:26 (66.41.8.98)
A good product is much, much, much, much more than a bill of material. There is great deal of know-how that goes into each good product, and a home builder may or may not have access to it, may or ma .......
204: Amp/Preamp Asylum, IMHO (0.00)
Posted by Legendre on 2006-05-24, 16:41:42 (66.41.8.98)
If you are in a position to build a piece - and do it in a workmanlike fashion - I'd tend to take the DIY route. Consider a Bill of Materials priced at $600: By the time it's built, tested, warrantied .......
205: Dynaco-Doctor Forum, Re: Mapletree Audio "special red stereo 70 driver module" (0.00)
Posted by Legendre on 2006-05-24, 06:55:41 (66.41.8.98)
According to Mapletree, the tube compliment is 2X each 6SL7 and 6SJ7.. http://www.mapletreeaudio.com/ It appears to use the 6SL7 as a Williamson-style phase splitter & driver. The 6SJ7 (a sharp-cutoff .......
206: Dynaco-Doctor Forum, Re: Installed 23 stepped 250K attenuator, high volume (0.00)
Posted by Legendre on 2006-05-24, 06:02:01 (66.41.8.98)
...Installed it right... If the PAS was working normally before you did the work, it's pretty safe to say that you *didn't* install it right. I've installed the DACT attenuators for both volume and b .......
207: Dynaco-Doctor Forum, Re: external DC power supply for PAS? (0.00)
Posted by Legendre on 2006-05-23, 17:07:32 (66.41.8.98)
For the filaments? Probably just fine.. BUT - If you want to improve sonics through regulation, I'd go after the HV supplies first, not the filaments. .......
208: Dynaco-Doctor Forum, Re: 5Z3 as rectifier tube in ST70? (0.00)
Posted by Legendre on 2006-05-23, 16:59:33 (66.41.8.98)
A 5Z3 is essentially a 5U4G with a different base. The 5U4G is a suboptimal replacement for a 5AR4. A 5U4G will 'work' in an ST-70, but the voltages will run low, and tend to sag more under load. I'd .......
209: Dynaco-Doctor Forum, Re: ST-70 PCB: What's this part? (0.00)
Posted by Legendre on 2006-05-23, 16:50:21 (66.41.8.98)
(see my reply in Tube-DIY) .......
210: Tube DIY Asylum, Re: ST-70 PC board parts question... (0.00)
Posted by Legendre on 2006-05-23, 16:41:16 (66.41.8.98)
1) The parts you describe are silver-mica capacitors. They might be part of the feedback loop. 2) mmF is equivalent to picofarad (pF) 3) I'd replace the selenium as a matter of course, along with the .......
211: Amp/Preamp Asylum, What type of speaker posts does it have? (0.00)
Posted by Legendre on 2006-05-23, 16:30:33 (66.41.8.98)
Are they the traditional black & red 5-way binding posts, or something like Cardas - where the markings can be almost invisible? (or something else entirely?) One problem with Cardas posts (and simila .......
212: Dynaco-Doctor Forum, I'm with Dave on this.. (0.00)
Posted by Legendre on 2006-05-19, 17:31:44 (66.41.8.98)
Nothing about that chassis speaks 'reliable' to me; just redo the works. The transformers are what you *really* want, anyway. Those look like photoflash capacitors in there.. a very popular thing to d .......
213: General Asylum, Re: The absolute polarity of CDs relative to vinyl records (0.00)
Posted by Legendre on 2006-05-19, 07:04:19 (66.41.8.98)
FWIW - All of our preamps (from the discontinued P-2, to the current MP-3 and MP-1) have always had an absolute phase switch (marked "normal/invert" on the panel). And yes, we still occasionally recei .......
214: Dynaco-Doctor Forum, Thanks Joe /nt (0.00)
Posted by Legendre on 2006-05-17, 18:57:23 (66.41.8.98)
.......
215: Amp/Preamp Asylum, Not sure what you are asking, here (0.00)
Posted by Legendre on 2006-05-17, 17:59:30 (66.41.8.98)
Connecting the computer to drive an external power amp is very easy, you just need a cable to go between the line-out and the input of the power amp - $5. If your $200 budget includes the power amp, s .......
216: General Asylum, Doesn't seem to affect Svetlana (0.00)
Posted by Legendre on 2006-05-17, 17:50:59 (66.41.8.98)
I'm not looking forward to what the Chinese tubes are going to cost when Russia goes out of the business, either. While it would be a bitter loss, I believe that this article only refers to the Refl .......
217: General Asylum, Re: Russian Tubes at Risk (0.00)
Posted by Legendre on 2006-05-16, 16:24:01 (66.41.8.98)
Yes, I heard this tale.. a couple of months ago. Can anyone confirm/deny if this is just a rehasing of the old news, or if these are new (within the last week or two) developments? .......
218: Dynaco-Doctor Forum, PING Joe C - PAS RIAA mod question (0.00)
Posted by Legendre on 2006-05-16, 16:19:40 (66.41.8.98)
Joe, Based on the advice you gave in: http://db.audioasylum.com/cgi/m.mpl?forum=dynaco&n=7492&highlight=47K+feedback+resistor+Joe+Curcio&r=&session= I had a quick question. 1) "5. Replace the 2750pf R .......
219: Vintage Asylum, Link is 404 from my end /nt (0.00)
Posted by Legendre on 2006-05-15, 15:48:10 (66.41.8.98)
.......
220: Dynaco-Doctor Forum, Tube amp books (0.00)
Posted by Legendre on 2006-05-15, 15:39:47 (66.41.8.98)
Here are some sources for typical tube amp tech. literature: www.newsensor.com www.tubesandmore.com Or, Allen Wright's excellent tube cookbooks: www.vacuumstate.com/cookbooks.htm .......
221: General Asylum, www.getfirefox.com /nt (0.00)
Posted by Legendre on 2006-05-15, 15:28:48 (66.41.8.98)
.......
222: Tube DIY Asylum, Re: What about glow tubes? (0.00)
Posted by Legendre on 2006-05-15, 06:55:43 (66.41.8.98)
In the most basic application, glow tubes act as simple shunt regulators; think of them as gas-filled zener diodes. They have several limitations: 1) Maximum current output of a regulated stage is equ .......
223: Tube DIY Asylum, "Oh no, not again!" (0.00)
Posted by Legendre on 2006-05-15, 06:37:29 (66.41.8.98)
I've been following the story of the besieged Saratov (Reflector) plant for several months. What troubles me a bit is the timing of this story - as several months ago, I was left with the impression t .......
224: Dynaco-Doctor Forum, It varies (0.00)
Posted by Legendre on 2006-05-14, 13:37:28 (66.41.8.98)
I have a pair of older Ruby branded EL-34 that are clearly made by Tesla/JJ (Slovakia). It sounds like yours (winged =C=) were made by Svetlana, in St. Petersburg Russia. .......
225: Dynaco-Doctor Forum, Re: New to Forum (0.00)
Posted by Legendre on 2006-05-14, 13:30:08 (66.41.8.98)
A Variac is a continuously variable autotransformer; it allows you to control how much voltage is supplied to to a piece of equipment, from 0 to 120V - and some go to 150V - but the extra range is rea .......
226: Dynaco-Doctor Forum, Re: New to Forum (0.00)
Posted by Legendre on 2006-05-14, 07:31:07 (66.41.8.98)
Interesting about the mid-late 70's computer building.. I've got a shelved Altair 8800 restoration project; really should finish that guy up. The cosmetics are just fine on it, but it had a small-ish .......
227: Vinyl Asylum, belt / direct drive (0.00)
Posted by Legendre on 2006-05-12, 18:54:37 (66.41.8.98)
The PL-41 is belt drive; the PL-50/51 are direct drive. .......
228: Vinyl Asylum, Re: Vintage Pioneer PL-41 (0.00)
Posted by Legendre on 2006-05-12, 17:19:48 (66.41.8.98)
Very, VERY nice full-sized Japanese table.. I had one for years. Does yours have the nice walnut veneer base, and the clear acrylic cover? The platter, bearing, motor etc are all top quality. For some .......
229: Vintage Asylum, Fake Rubycon electrolytics - a warning (0.00)
Posted by Legendre on 2006-05-12, 16:26:01 (66.41.8.98)
(this is a cross-posted note; see the full post in Tube-DIY asylum) .......
230: Tube DIY Asylum, Fake Rubycon electrolytics - a warning (0.00)
Posted by Legendre on 2006-05-12, 16:23:22 (66.41.8.98)
Be on the lookout for electrolytic caps marked 'Rubycon', but which are in fact nasty Chinese fakes. A friend recently purchased a batch of supposedly Rubycon 47 & 22uF / 450V parts that were nothing .......
231: Vintage Asylum, Re: Heathkit SA-2 restore woes (0.00)
Posted by Legendre on 2006-05-12, 16:15:15 (66.41.8.98)
Two things: 1) By "run it up", I thought that a variac was implied (as opposed to "switch it on, and cross your fingers"). Do people really tinker with old / unknown equipment on a full AC line? That' .......
232: Vintage Asylum, Re: Heathkit SA-2 restore woes (0.00)
Posted by Legendre on 2006-05-12, 08:25:26 (66.41.8.98)
Run it up with the output tubes removed from the chassis. If the rectifier behaves, and the voltages seem normal (normal, as in higher than usual - but stable), then suspect the output tubes and/or th .......
233: OTL Asylum, Re: Interconnects between MP-1 and MA 2.2 (0.00)
Posted by Legendre on 2006-05-12, 07:47:13 (66.41.8.98)
Just curious, did you order the Mogami 2534 or 3173 wire? At $0.59, I'd assume the former. While the latter is designed as a digital AES/EBU cable, it's occasionally suggested as an analog cable. The .......
234: Dynaco-Doctor Forum, Re: New mullards in ST-70? (0.00)
Posted by Legendre on 2006-05-11, 16:16:45 (66.41.8.98)
Do a search of this very forum, there are several (recent) threads on the topic. Consensus: Do not use the 'Mullard' EL-34, at least until the issues are fixed. .......
235: Dynaco-Doctor Forum, Re: Dynakit parts. (thermistors?) (0.00)
Posted by Legendre on 2006-05-10, 05:37:41 (66.41.8.98)
It's a Keystone CL-90 CIL (current inrush limiter). CILs are a type of NPO thermistor - that is, their internal resistance *falls* as the device conducts current, and heats up. They are normally insta .......
236: Amp/Preamp Asylum, Two more (0.00)
Posted by Legendre on 2006-05-09, 18:13:36 (66.41.8.98)
There is another fine metal polish called 'Flitz', close to Simichrome, that is totally non-abrasive; it will remove light surface tarnish and nothing else. Also, NEVR-DULL is excellent for cleaning a .......
237: Dynaco-Doctor Forum, Thanks for fixing this Joe /nt (0.00)
Posted by Legendre on 2006-05-09, 16:17:52 (66.41.8.98)
.......
238: Vintage Asylum, Re: Red Tiny Chief caps: replace or not? (0.00)
Posted by Legendre on 2006-05-09, 06:21:52 (66.41.8.98)
I had one of these amplifiers, about ten years ago.. it may not have been a 2420, but it was a very similar model. Also, it contained a number of Tiny Chief caps. They were very troublesome parts in m .......
239: Dynaco-Doctor Forum, Hm, that's interesting (0.00)
Posted by Legendre on 2006-05-08, 06:38:03 (66.41.8.98)
Ok, I'll admit that the schematic is not marked as to sections, and I made the (reasonable) assumption that the cascode was built from the sections of a single tube. We can just take it as a given tha .......
240: Vinyl Asylum, Re: How did this journey begin for you? Long!! (0.00)
Posted by Legendre on 2006-05-06, 17:08:02 (66.41.8.98)
By 1991 I had almost completely lost interest in music listening. I bought the cock & bull about CD sound in the mid-80s, sold ALL of my vinyl, and by the early 90's I just wasn't listening anymore (s .......
241: Dynaco-Doctor Forum, Re: tube matching in ST-70 upgrade driver board (0.00)
Posted by Legendre on 2006-05-06, 16:44:03 (66.41.8.98)
From the look of the schematic, here is what would be ideal: L & R tubes should be well matched to one another; but tbey don't exactly require internally matched sections. For instance, if you find a .......
242: Dynaco-Doctor Forum, Re: mod help! (0.00)
Posted by Legendre on 2006-05-05, 19:15:45 (66.41.8.98)
To 'jumper' a part, means to bypass it with a piece of wire. You can remove the caps if you want, but the effect will be the same either way. .......
243: Vinyl Asylum, Re: Kenwood KD=2055--anyone know how to remove the platter? (0.00)
Posted by Legendre on 2006-05-04, 16:33:07 (66.41.8.98)
If it's like most Japanese tables, the platter is secured via an interference fit on the spindle shaft taper. Normally, you grasp the platter via a set of fingerholes on the top, and pull it straight .......
244: Vinyl Asylum, Funny you should mention the Quiex (0.00)
Posted by Legendre on 2006-05-04, 16:24:37 (66.41.8.98)
I just picked up a copy of The Emerald Forest soundtrack, and found (via Google) that it was supposedly a Quiex VV pressing. I took it outdoors, and it passed the light test - and that's what got me w .......
245: Dynaco-Doctor Forum, A couple of details (0.00)
Posted by Legendre on 2006-05-04, 16:20:59 (66.41.8.98)
There is no reason that the board cannot be used as a stand-alone RIAA phono preamp. As was already mentioned, you will need to build a PSU to run the filaments (DC) and high-voltage. Also - the PAS-2 .......
246: Dynaco-Doctor Forum, Re: Custom Dynaco ST-35 - photos (0.00)
Posted by Legendre on 2006-05-04, 16:11:08 (66.41.8.98)
Bob, Mmm.. handbuilt goodness - Nice work! Can't go wrong with wood & metal; they are the sutff of the ages. One teeny little suggestion. If you ever do another amp like this in the future, rotate the .......
247: Dynaco-Doctor Forum, More HexFred talk (0.00)
Posted by Legendre on 2006-05-04, 16:01:11 (66.41.8.98)
Doug, Heh, I'd totally ignored the fact that the Dynaco uses a conventional full-wave rectifier.. Yes, the common-cathode dual Hexfred should work just great in that app. In fact, we use the dual 600V .......
248: Vinyl Asylum, Virgin VInyl musings and questions (0.00)
Posted by Legendre on 2006-05-03, 16:34:44 (66.41.8.98)
I've always used the 'light' test to identify / verify pressings on virgin vinyl - hold it up to a bright light, and if it appears translucent brown, it's VV. Has anyone found this simple test to be i .......
249: Vinyl Asylum, Re: MC40's / Sansui 1000A tube receiver for preamp. (0.00)
Posted by Legendre on 2006-05-03, 16:22:21 (66.41.8.98)
Holy moly, a 1000A for a preamp? Those things are big enough to live in! ;-) Tell me, does yours have the orange metallic finish? Just curious, who are you planning to have upgrade the PAS-2? Several .......
250: Vinyl Asylum, ASMS (0.00)
Posted by Legendre on 2006-05-03, 07:38:13 (66.41.8.98)
Atma-Sphere, naturally.. A pair of M-60 Mk.II and an MP-1 preamp, built with my own hands. Hey, did you hear that? That's the sound of everyone not being surprised. ;-) .......
251: Dynaco-Doctor Forum, Re: Standby Switch in ST-70 (0.00)
Posted by Legendre on 2006-05-03, 07:17:27 (66.41.8.98)
Something like this: http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=92457&Row=391432&Site=US 8A, 1200V HexFred diode, in TO-247AC package. Note that HexFreds almost never use the common .......
252: Vinyl Asylum, Some Vangelis picks (0.00)
Posted by Legendre on 2006-05-02, 06:59:01 (66.41.8.98)
Blade Runner is hard to trump, but there are several other truly fantastic works in his catalog.. Here's some Vangelis you can't live without: - China (a sublime masterpiece) - Soil Festivities (alrea .......
253: OTL Asylum, Re: MP-3 DIY tweaking - possibility, resources? (long) (0.00)
Posted by Legendre on 2006-05-02, 06:42:17 (66.41.8.98)
Of all of our products, the MP-3 has probably changed the least over its production life. Most of the update/upgrade work is fairly straightforward, and should not be a problem for someone with genera .......
254: Dynaco-Doctor Forum, Re: Standby Switch in ST-70 (0.00)
Posted by Legendre on 2006-05-02, 06:04:13 (66.41.8.98)
In the past, I've had good luck installing the standby switch in series with the heater circuit (5V winding) of the rectifier tube. Takes a few seconds to come on, but it's guaranteed to not produce a .......
255: Vintage Asylum, Agreed (0.00)
Posted by Legendre on 2006-04-30, 07:16:55 (66.41.8.98)
In terms of power supply audibility, HexFreds embody most of the desirable characteristics of vacuum diodes, without the inherent high-ish impedance and voltage sag. Keep in mind that rectifiers don't .......
256: Dynaco-Doctor Forum, Re: Modifying PAS-3X to drive lower input impedance amps (0.00)
Posted by Legendre on 2006-04-29, 19:28:11 (66.41.8.98)
Hey Freud, I don't know the factory method, but I'm guessing that it involves replacing the stock 1uF output coupling caps with larger parts. To get the same response into 10K as 100K, you'd need 10uF .......
257: Vinyl Asylum, Empire tonearm question - tracking force (0.00)
Posted by Legendre on 2006-04-29, 06:55:24 (66.41.8.98)
The stock Empire tonearms have a knob which is used to regulate tracking force. The knob is marked with a series of incremental lines, one of which has a zero next to it. Question - what is the increm .......
258: Vintage Asylum, Re: are all hexfreds the same (0.00)
Posted by Legendre on 2006-04-29, 06:44:03 (66.41.8.98)
HexFred rectifiers used to be rather pricey, when they first came to market; prices today are dramatically lower. Since they come in many current / voltage ratings, and I don't know the exact part you .......
259: Dynaco-Doctor Forum, Re: Bias teeder toddering between sides (0.00)
Posted by Legendre on 2006-04-27, 07:45:56 (66.41.8.98)
This is a typical issue when two channels share the same power supply (like in an ST-70). If the bias goes up in one channel, it falls off in the other (the converse is also true). At least the bias i .......
260: Dynaco-Doctor Forum, Re: Illinois caps - for coupling? (0.00)
Posted by Legendre on 2006-04-27, 06:21:07 (66.41.8.98)
Mike, Thanks for the information. I'll order up some samples, and drop them into one of our M-60s. So which are these supposed to compare with, the Black Beauty and so on? I've heard the Xicon MPP par .......
261: Vintage Asylum, Re: The lower end Grado's sound quite nice and are very (0.00)
Posted by Legendre on 2006-04-26, 16:27:56 (66.41.8.98)
Not really vintage, but I'd give this one a big hearty 'second that!'. The lower end (eg SR-80) Grado phones have no equal, at their price. Grado's basic design philosophy is quite solid. .......
262: Dynaco-Doctor Forum, Illinois caps - for coupling? (0.00)
Posted by Legendre on 2006-04-26, 16:21:06 (66.41.8.98)
Now I've heard this three times, that people like a certain Illinois cap for coupling use in vintage gear.. Which series of caps are we talking about here? Illinois makes several series / compositions .......
263: Dynaco-Doctor Forum, I'm sorry, the correct answer was 'shotgun' (0.00)
Posted by Legendre on 2006-04-25, 15:53:30 (66.41.8.98)
Sometimes, you just have to shotgun it. Like fixing a voltage regulator on older an AR preamp.. I have almost no idea how they work, but I've fixed several of them. You can guess how I mananged that.. .......
264: Dynaco-Doctor Forum, This does alter the feedback (0.00)
Posted by Legendre on 2006-04-25, 15:45:38 (66.41.8.98)
It's not hype, the theory behind it is sound. One thing to keep in mind, is that switching from the 16 to the 8 ohm tap will decrease the overall amount of negative feedback. When they refer to alteri .......
265: Vinyl Asylum, Re: Connection Question: Quad 44 Preamp as Phono (0.00)
Posted by Legendre on 2006-04-24, 17:09:50 (66.41.8.98)
From what you describe, the problem is that you are using the 'monitor' switch on the Quad 44. Try disengaging the monitor switch, and see what you get. Monitor would normally mute the phono input in .......
266: Vinyl Asylum, Misc classical vinyl haul - some gems? (0.00)
Posted by Legendre on 2006-04-24, 16:32:39 (66.41.8.98)
Had a little classical find at the local thrift store.. and I'm just getting around to looking at what I've got. I'll say up front that I'm *not* much of a classical guy, but this stuff looked interes .......
267: Dynaco-Doctor Forum, Re: How to calculate bias when using dual pots? (0.00)
Posted by Legendre on 2006-04-24, 07:09:29 (66.41.8.98)
Ohm's law (E=IR) applies.. E = 0.045 * 2.8 E = 0.126V for 45mA through 2.8ohms .......
268: Amp/Preamp Asylum, Yes, some Atma-Sphere are switchable (0.00)
Posted by Legendre on 2006-04-23, 06:40:06 (66.41.8.98)
Atma-Sphere M-60 Mk.II.3 (long narrow chassis) is switchable, as are the MA-1 Mk.II.3, MA-1 Silver Edition and (so far..) the MA-1 Mk.III. The first MA-2 Mk.III (we are just producing these) are also .......
269: OTL Asylum, Re: More question about MP-3 pre-amp (0.00)
Posted by Legendre on 2006-04-22, 15:23:17 (66.41.8.98)
The MP-3 does not have input coupling caps; the inputs are direct to the tube grids via the 250K / 500K volume control. .......
270: Dynaco-Doctor Forum, Re: mklll 11.2 ohm bias resistor bad (0.00)
Posted by Legendre on 2006-04-21, 17:10:00 (66.41.8.98)
Two thoughts... - Replace all of the 11R2 (11.2 ohm) resistors with high-quality 10R (10 ohm) parts. Calculate the correct voltage drop for 10 vs 11.2 and call it good. - Start with a value larger tha .......
271: Dynaco-Doctor Forum, More CD thoughts (OT) (0.00)
Posted by Legendre on 2006-04-21, 17:04:08 (66.41.8.98)
You're thinking correctly here.. I've done some fairly novel research on this subject, and have come to three (I believe) important conclusions. The guys in the digital asylum might want to slay me fo .......
272: Vintage Asylum, Re: So much for getting a "deal" on Ebay (0.00)
Posted by Legendre on 2006-04-20, 16:48:58 (66.41.8.98)
Grant, It sure seems like ebay rules are structured to help the seller No.. eBay rules are structured to help eBay . Once you are willing to accept this fact, much of it starts to make perfect sense. .......
273: OTL Asylum, Re: Is Novacron kit still exist? or where can I (0.00)
Posted by Legendre on 2006-04-20, 16:38:28 (66.41.8.98)
We have not produced chassiswork for the Novacron since the mid-1990s. For all practical purposes, the circuit topology is the same as the M-60 / MA-1, and only differs in implementation. .......
274: Amp/Preamp Asylum, Big Class-A iron does exist (0.00)
Posted by Legendre on 2006-04-20, 16:20:49 (66.41.8.98)
We build two large class A OTL amplifiers, the MA-2 (220 watts) and MA-3 (480 watts).. and with tubes, nonetheless. And you are correct - they are physically very large, and quite heavy - 206 lbs for .......
275: Amp/Preamp Asylum, Re: Is there anything to be gained by using shorting plugs on rca inputs on Halo JC-1 amps when using the XLR inputs? (n (0.00)
Posted by Legendre on 2006-04-20, 06:41:35 (66.41.8.98)
It depends on how the Halo's input is designed. On some amps with both RCA and XLR inputs, the RCA input is simply an extension of pins 1 & 2 on the XLR input. With these designs, installing a shortin .......
276: Amp/Preamp Asylum, Re: Unused channels on a multi-channel amp (0.00)
Posted by Legendre on 2006-04-20, 06:28:47 (66.41.8.98)
Typical of the misinformation in these forums It's just good, common-sense practice to short unused inputs. I never stated that it was a requirement, but in light of the potential (even if theoretica .......
277: Amp/Preamp Asylum, Re: For the sake of clarity (0.00)
Posted by Legendre on 2006-04-20, 06:07:35 (66.41.8.98)
To answer the first part of the question - yes, there are a broad range of bias points for AB amplifiers. In some cases, the A operation is limited to just a few milliwatts, whereas others might remai .......
278: Vintage Asylum, A round of thanks (Mac MC-30 rebuild) (0.00)
Posted by Legendre on 2006-04-19, 16:39:23 (66.41.8.98)
Hearty thanks to everyone who provided info & insight on my McIntosh MC-30 rebuild (more like repair and maint.) project last month. The amps have been back with the owner for a couple of weeks, and b .......
279: Vintage Asylum, Re: I am only down to motorboating on fixing my tube amp- clean suggestions? (0.00)
Posted by Legendre on 2006-04-19, 16:32:25 (66.41.8.98)
So remind me - what was the main reason for motorboating again? Bad electrolytic filter caps in the power supply is the classic cause of motorboating .......
280: Amp/Preamp Asylum, Re: Unused channels on a multi-channel amp (0.00)
Posted by Legendre on 2006-04-19, 16:28:41 (66.41.8.98)
Nope, no problem.. just leave the inputs shorted on the unused sections. As far as rotating through the unused sections, it's a nice idea in theory (keep wear / break-in even), but I don't see it as h .......
281: Amp/Preamp Asylum, For the sake of clarity (0.00)
Posted by Legendre on 2006-04-19, 16:22:32 (66.41.8.98)
What you are describing - first few watts (sometimes milliwatts) at class A, and then no longer class A - is simply an AB mode amplifier, not "A/AB mode". A/AB would imply that the class of operation .......
282: Dynaco-Doctor Forum, Re: It lives. (0.00)
Posted by Legendre on 2006-04-19, 16:01:17 (66.41.8.98)
Supreme! Congratulations... sorry if I caused you any hand-wringing over the startup. .......
283: Dynaco-Doctor Forum, Re: Vindicated (0.00)
Posted by Legendre on 2006-04-19, 15:59:46 (66.41.8.98)
Yep, most all of the consumer-market CD players are pretty much exactly the same, and they all sound similarly crappy. That, and they break. Hardly matters what you spend, as none of them really work .......
284: Dynaco-Doctor Forum, Doh. (0.00)
Posted by Legendre on 2006-04-19, 06:13:42 (66.41.8.98)
Robert, Sorry about this; the fact that you were running Joe's PSU board had totally escaped me when I wrote the previous post. Too many threads, too many posts, too many details.. when I saw that you .......
285: Dynaco-Doctor Forum, Voltages are not right (0.00)
Posted by Legendre on 2006-04-18, 17:07:57 (66.41.8.98)
According to the PAS-3 manual, those voltages are a way off.. and most notably, the voltages on 'triangle' and 'square' are exactly the same - this should not be. Something is clearly wrong, here. The .......
286: Dynaco-Doctor Forum, Re: weekend update (0.00)
Posted by Legendre on 2006-04-18, 07:02:41 (66.41.8.98)
Also, when I apply a signal around 23K I get a pronounced noise from the ST-70 Chassis! There is a high whine, that rises and falls with the freq tuning. It sounds just like tuning a shortwave radio, .......
287: Dynaco-Doctor Forum, Re: Pat-4 hissy fit (0.00)
Posted by Legendre on 2006-04-17, 06:09:31 (66.41.8.98)
Unless you are specifically interested in learning to repair solid-state equipment, I'd send it down the road. From your description, the unit can be sold as 'working', with a fair mention of the hiss .......
288: Dynaco-Doctor Forum, Re: Dirty AC mains and the fancy powercord business (0.00)
Posted by Legendre on 2006-04-15, 07:06:21 (66.41.8.98)
About ten years ago, I heard that an engineer at one of the well-known analog mastering studios (it may have been George Massenburg at The Mastering Lab) would shut down and disconnect all computers i .......
289: Amp/Preamp Asylum, Re: Is it possible to calculate the voltage output of an amp? (0.00)
Posted by Legendre on 2006-04-15, 06:38:39 (66.41.8.98)
First, you need to understand that *any* amplifier delivering 40 watts into 8 ohms is producing 17.889 volts at 2.236 amps. These are the laws of electronics, and the design of the amplifier has no be .......
290: OTL Asylum, The seller says.. (0.00)
Posted by Legendre on 2006-04-15, 05:22:02 (66.41.8.98)
I sent an email to the seller, and received a reply from a Mr. Craig Merz, Silver City NM, USA. Interestingly enough, he said that the amps are built there, in Silver City NM - from this, one would i .......
291: Amp/Preamp Asylum, Good rule (0.00)
Posted by Legendre on 2006-04-14, 16:37:17 (66.41.8.98)
Obviously, it depends a lot on who made the components.. but David's rule of thumb is essentially correct. A well made set of electronics can outlast the best of us, especially if they were actually d .......
292: Amp/Preamp Asylum, Might be a stretch for $1K - BUT (0.00)
Posted by Legendre on 2006-04-14, 16:25:46 (66.41.8.98)
Might be a stretch for $1K, but the small Atma-Sphere monos (M-50, M-60) really shine on the Quad ESL. You might be able to snag a pair of older M-50/60 in the $1200-1500 range, though.. if you are go .......
293: Dynaco-Doctor Forum, Dirty AC mains and the fancy powercord business (0.00)
Posted by Legendre on 2006-04-14, 16:11:22 (66.41.8.98)
Just yesterday, I was wondering about when the whole business of botique power cords and conditioners got rolling. If I had to guess, I'd say somewhere in the early 1990's. Now, assuming that is rough .......
294: OTL Asylum, Re: Loadings resistors in M60 (0.00)
Posted by Legendre on 2006-04-14, 15:54:10 (66.41.8.98)
The parts you want to play with are the 100K resistors running from pins 2 & 3 to ground. Don't tamper with the 4K75 parts, as they (and the 2M parts) are elements in the NFB loop. I prefer putting a .......
295: OTL Asylum, Chinese unit? (0.00)
Posted by Legendre on 2006-04-14, 15:32:11 (66.41.8.98)
I've seen mention (via google) of 6AS7-based Chinese made OTL amps, being sold on eBay without warranties. This may be an example. The amps shown in the link do have a Chinese-y look to them, but they .......
296: Dynaco-Doctor Forum, Re: running ampswith a variac (0.00)
Posted by Legendre on 2006-04-11, 16:22:42 (66.41.8.98)
Check the Mk.III manual - IIRC, it allows up to 125VAC input. But, running with a Variac should not have any real impact on the sound, so long as the Variac is rated for the load. Some designs (like t .......
297: OTL Asylum, Re: Question and comment on tube matching (0.00)
Posted by Legendre on 2006-04-11, 16:02:26 (66.41.8.98)
Lew, FWIW - the two matched quads which I received from New Sensor seemed *very* well matched, at least in terms of DC. When setting up the amps, I set a nominal bias voltage with the control, and use .......
298: Dynaco-Doctor Forum, Re: Metal replacement switches (0.00)
Posted by Legendre on 2006-04-10, 16:52:40 (66.41.8.98)
I don't think I've ever seen this type of switch with a metal slider. The problem with this, is that the moving switch contact is directly attached to the plastic slider, and relies on the plastic for .......
299: OTL Asylum, Re: Not Defending the Gunslingers, but... (0.00)
Posted by Legendre on 2006-04-10, 07:27:11 (66.41.8.98)
And really, we haven't had a flaming troll here since over a year ago, when some clown was posting garbage using the moniker 'billlayer' (which I have never used). Those posts were rightfully removed. .......
300: Dynaco-Doctor Forum, Re: Is there a way to check my GZ34 before I even start? (0.00)
Posted by Legendre on 2006-04-10, 06:49:38 (66.41.8.98)
Cathode is pin 8, plates are pins 4 & 6.. check with an ohmmeter (there should be infinite resistance between all three of these pins). However, unless the tube has a cold, dead short, this will not t .......
301: Dynaco-Doctor Forum, Re: So what do I do? (0.00)
Posted by Legendre on 2006-04-09, 17:01:14 (66.41.8.98)
Peter, Your comments echo my exact feelings on the subject (see my recent post). In short, the SS rectifier gives you a much wider safety margin over the tube (5AR4 in this case). About the CopperCap .......
302: Dynaco-Doctor Forum, Re: So what do I do? (0.00)
Posted by Legendre on 2006-04-09, 16:05:25 (66.41.8.98)
To build the test rectifier, any octal tube base or octal plug will work, so long as it has pins 4,6 and 8 intact. If you've ever seen the 'soild state replacement' rectifiers sold for guitar amps, th .......
303: Dynaco-Doctor Forum, Re: Rebuilt 70 ready for start up (0.00)
Posted by Legendre on 2006-04-09, 09:18:36 (66.41.8.98)
I would definitely use the 'quad cap replacement' procedure, as it's most critical to be sure that everything is OK in the high voltage supply wiring. Discovering errors in the signal circuit is usua .......
304: Dynaco-Doctor Forum, My bad - a clarification (0.00)
Posted by Legendre on 2006-04-09, 07:42:37 (66.41.8.98)
While a theoretical 'perfect' square wave has infinite *bandwidth*, it does *not* contain all frequencies. In fact, it would contain all odd integer harmonics eg, 3rd, 5th, 7th in an infinite series. .......
305: Dynaco-Doctor Forum, Re: PAS3 Balance problem, Solved (0.00)
Posted by Legendre on 2006-04-08, 17:57:25 (66.41.8.98)
The prono seems to distort the signal to an almost surprising degree. Nothing surprising about that. The phono section employs an RIAA equalization network, which tailors the frequency response to c .......
306: Dynaco-Doctor Forum, Re: File size is 484 KB NOT 484 MB - my error (0.00)
Posted by Legendre on 2006-04-08, 07:15:10 (66.41.8.98)
legendre:at:nerp:dot:net .......
307: Dynaco-Doctor Forum, Size doesn't add up (0.00)
Posted by Legendre on 2006-04-07, 16:35:52 (66.41.8.98)
A raw image 2017 X 1938 (and I'm assuming it's 32bpp true-color) should only be 119MB in size - not 500MB. What's using up the other 380MB? .......
308: OTL Asylum, Now who built those? (0.00)
Posted by Legendre on 2006-04-07, 16:01:02 (66.41.8.98)
I've never seen a set of Novacrons with a Mk.II (6SN7) style driver.. who built that set? Please don't say "You guys did", or I'm going to feel really foolish. .......
309: Dynaco-Doctor Forum, The basic advice (0.00)
Posted by Legendre on 2006-04-06, 16:32:51 (66.41.8.98)
Can I assume that the imbalance is the same at all volume levels? Poor balance is almost always related to the voltage amplifier(s) on the driver board, as opposed to an issue in the output section (a .......
310: Dynaco-Doctor Forum, Re: st70 bias shifting (0.00)
Posted by Legendre on 2006-04-05, 17:48:43 (66.41.8.98)
It sounds like the L & R bias controls are interacting? That is normal, when both channels share the same supply. Turn the bias up on one channel, it goes down in the other - and vice-versa. You liste .......
311: OTL Asylum, 6C33C-B & Novacron revisited (0.00)
Posted by Legendre on 2006-04-05, 16:50:26 (66.41.8.98)
It's been a decade since Atma-Sphere produced any 6C33C-B based amps, and even then the runs were small. Approximately 24 sets of Novacron (MA-1.5) were produced, with about a third of those being sol .......
312: Dynaco-Doctor Forum, Re: Do NOT Do It !!!!!! ST 70 Individual Bias Pots (0.00)
Posted by Legendre on 2006-04-04, 06:36:05 (66.41.8.98)
I've never seen individual bias pots as anything other than an (in)convenience measure to allow the running of unmatched tubes. I fail to see any advantage to individual pots, over single pots and wel .......
313: Vinyl Asylum, Festival of Light Classics / Classical (0.00)
Posted by Legendre on 2006-04-02, 08:54:03 (66.41.8.98)
Exact title is escaping me right now, and I'm too lazy to go downstairs and look. But, there is a box set titled 'A Festival of Light Classics' or 'A Festival of Light Classical Music' which is also a .......
314: OTL Asylum, Re: V-Cap Teflon for my MP-3 (0.00)
Posted by Legendre on 2006-04-01, 17:16:08 (66.41.8.98)
A rating of 400 volts DC is fine for any position in the MP-3 or MP-1. High voltage supplies (regulated) run between 225V and 265V, depending on type and revision. .......
315: OTL Asylum, Re: V-Cap Teflon for my MP-3 (0.00)
Posted by Legendre on 2006-03-31, 06:49:00 (66.41.8.98)
Bryan, I'm not sure which 47uF cap you are referring to. As far as coupling caps go, the complement in the MP-3 is: - 4 x 0.022 in phono stage (use AudioCap teflon or Vcap here) - 4 x 0.47 at output o .......
316: OTL Asylum, Re: Differences in (2) MP3 Preamp (0.00)
Posted by Legendre on 2006-03-30, 07:23:13 (66.41.8.98)
Is it possible that your MP-3 is or was a 235V unit? The toroid is an isolation transformer, used to supplement the electrostatic shields in the on-board transformers. They are generally used only on .......
317: Digital Drive, Re: Feeding active speakers directly from DAC - pro's and con's (0.00)
Posted by Legendre on 2006-03-29, 07:25:15 (66.41.8.98)
As long as the DAC output can properly control & drive the interconnect / load combo (questionable), there should be no need to insert a preamp in the chain. In the modern era of high-output line sour .......
318: Dynaco-Doctor Forum, Hum issue (0.00)
Posted by Legendre on 2006-03-28, 16:07:33 (66.41.8.98)
Which transformer(s) are humming? The only one which *might* hum is the power transformer - the outputs should be silent, as they are not passing any AC current, at idle. Try this - power up the amp w .......
319: OTL Asylum, Re: Trouble free Fourier Pantheres!! (0.00)
Posted by Legendre on 2006-03-28, 15:49:48 (66.41.8.98)
Thanks for the positive attitude but why should one not be a fan of the circuit? Hey now, just because I fail to be a 'fan' of the Futterman circuit, doesn't mean that I have a problem with it.. Jul .......
320: OTL Asylum, Re: Trouble free Fourier Pantheres!! (0.00)
Posted by Legendre on 2006-03-27, 16:59:34 (66.41.8.98)
It's really nice to hear that you've got a solid, working set of Pantheres.. these amps have taken quite a drubbing over the years, often due to the issues you mention re: electrolytic caps of questio .......
321: OTL Asylum, Re: M60 autobias (0.00)
Posted by Legendre on 2006-03-27, 16:44:52 (66.41.8.98)
A quick rundown: 1) Yes and No - No more than the standard bias/dc arrangment will offer clues that a tube has failed, by the sudden presence of a DC offset where there previously was none. The autobi .......
322: Digital Drive, Need Help - TEAC RW-H500 drive replacement (0.00)
Posted by Legendre on 2006-03-27, 16:05:01 (66.41.8.98)
I'm trying to repair a TEAC RW-H500 CD recorder; the drive is failing to read discs that work fine in multiple other players. Lots of 'disc error' and 'no disc' messages, as well as very odd, ugly sou .......
323: Dynaco-Doctor Forum, Re: One more thing then (0.00)
Posted by Legendre on 2006-03-27, 15:47:20 (66.41.8.98)
I've seen the tape/source switch fail a couple of times, and it's eaxctly as you describe. Unless you are trying to keep it 100% original, this is a good location for a DPDT mini-toggle. .......
324: Dynaco-Doctor Forum, Re: Current thoughts aren't too good. (0.00)
Posted by Legendre on 2006-03-27, 15:44:45 (66.41.8.98)
Note that the 'regular' Svetlana EL34 is almost totally identical to this so-called "Mullard" EL34. From what I could tell, the two tubes are produced on the same tooling, tho the Mullard seem to have .......
325: Vintage Asylum, Re: Whoops, 4311 - no B (0.00)
Posted by Legendre on 2006-03-27, 07:50:32 (66.41.8.98)
Aye, and blast I do. M-60 Mk.II w/ Zero autoformer, set to 1.5:1. Presents 12ohms to the the amp, which allows the amp to produce close to 80W continuous. But I chalk up the midrange failure to wear & .......
326: Dynaco-Doctor Forum, A drawing (0.00)
Posted by Legendre on 2006-03-27, 07:36:43 (66.41.8.98)
Here's a drawing for you to look at... http://nerp.net/~legendre/electronics/simple_6sn7.gif The 1M at the input should probably be a volume control pot.. 250K/500K whatever works for you. The value o .......
327: Vintage Asylum, Whoops, 4311 - no B (0.00)
Posted by Legendre on 2006-03-26, 13:12:23 (66.41.8.98)
Guess it's been a while since I looked at them.. they are actually original 4311s, not the B model. I looked at both PDF docs (thanks for the link) and I don't see much difference. The B seems to have .......
328: Vintage Asylum, JBL 4311B orientation? (0.00)
Posted by Legendre on 2006-03-26, 08:02:16 (66.41.8.98)
I've got a set of JBL 4311B control monitors, the style with the woofer on the 'top' of the cabinet. I assume that these speakers were meant to be set (or hung) on their sides, in the front of a sound .......
329: Dynaco-Doctor Forum, Re: ...Me too! - A simple linestage plan (0.00)
Posted by Legendre on 2006-03-26, 07:53:07 (66.41.8.98)
If you're looking to scratch-build an entry-level linestage project, with really decent sound, I may have just the ticket for you. Think you can handle a project that uses two 6SN7, two caps and about .......
330: Vintage Asylum, Class-A does not imply constant current (0.00)
Posted by Legendre on 2006-03-25, 06:59:28 (66.41.8.98)
The other is Class A operation. Class A stage draws the same high current at zero and full output power Class-A operation is defined by conditions under which the device (tube or transistor) conduct .......
331: Dynaco-Doctor Forum, Re: pas 3x input (0.00)
Posted by Legendre on 2006-03-25, 05:58:20 (66.41.8.98)
If you're going to try playing the guitar through the stereo, you need to really watch the volume settings. Multi-way loudspeakers for music listening are not the same as the drivers used in instrumen .......
332: Dynaco-Doctor Forum, Re: Tone control Bypass? (0.00)
Posted by Legendre on 2006-03-24, 16:22:50 (66.41.8.98)
Hey, nothing wrong with being a Hi-Fi guy..! in fact, it's probably much better for your sanity and finances in the long run. Vintage Hi-Fi is a boatload of fun, and if you are careful with your purch .......
333: Dynaco-Doctor Forum, PAS 3X tone contols (0.00)
Posted by Legendre on 2006-03-24, 09:46:36 (66.41.8.98)
While I was writing my original post, the whole PAS 3 vs. 3X thing was nagging at me in the back of my mind.. I couldn't remember what the distinction was. Anyway, thanks for pointing out the special .......
334: Dynaco-Doctor Forum, Re: PAS3X Upgrade Hints (ramble) (0.00)
Posted by Legendre on 2006-03-23, 17:05:45 (66.41.8.98)
"Also, it seems like many of you pull out some switches & filters. I would rather leave in any useful funtionality. (I like to play with the settings). What are the reasons to pull out the functions?" .......
335: Vintage Asylum, Re: Scott LT-110B tuner - common problem? (0.00)
Posted by Legendre on 2006-03-23, 06:44:51 (66.41.8.98)
Hmm.. very interesting info. I'm pretty sure that my 110B has the 6U8A, and not the genuine 6U8 as you mention. The unit has been carefully aligned by a friend who is a competent EE and tube/analog gu .......
336: Dynaco-Doctor Forum, Re: mlll output transformers test (0.00)
Posted by Legendre on 2006-03-22, 16:39:32 (66.41.8.98)
First premise of good troubleshooting (when you've worked on it already): If there is a problem, it's probably because of something *you* did. Go back and check all of your work. Better yet, have a fr .......
337: Vintage Asylum, Scott LT-110B tuner - common problem? (0.00)
Posted by Legendre on 2006-03-21, 17:25:19 (66.41.8.98)
I've got a Scott LT-110B here, and it is exhibiting what I have been told is a common problem. But no info on how to fix it.. When the tuner is tuned 'dead-on' to a station (per the meter, and per the .......
338: Dynaco-Doctor Forum, Re: PAS3 preamp input levels (0.00)
Posted by Legendre on 2006-03-21, 17:10:55 (66.41.8.98)
Good advice, and I'll add a little more.. The PAS phono input will take any typical moving-magnet cartridge you care to put on it. They are not appropriate for ceramic or crystal phono cartridges, but .......
339: Dynaco-Doctor Forum, Re: PAS3X Phono trouble (0.00)
Posted by Legendre on 2006-03-21, 16:56:51 (66.41.8.98)
Reflow the solder joints associated with the problem jack(s) on the PAS, and make sure your cables are not defective (intermittent). If the inner contact on the jack is loose, you can tension it by pu .......
340: Vinyl Asylum, TROLL'D! (nt) (0.00)
Posted by Legendre on 2006-03-19, 17:53:25 (66.41.8.98)
nt .......
341: Dynaco-Doctor Forum, I'd call it a fact (0.00)
Posted by Legendre on 2006-03-18, 08:49:49 (66.41.8.98)
As someone who builds (and hears a lot of) new equipment for a living, I can tell you that break-in is absolutely *not* a myth. Wire, resistors, capacitors all have their own timetables as well - they .......
342: Vinyl Asylum, A Fifth of Beethoven for you, sir (plus Blondie & Ramones) (0.00)
Posted by Legendre on 2006-03-18, 07:51:16 (66.41.8.98)
While Ludwig didn't actually 'sell out' to disco, he could only spin in his grave as Walter Murphy & the Big Apple Band 'turned him out' (if you know what I mean) via A Fifth of Beethoven. The disco e .......
343: Vinyl Asylum, Well, yes and no.. some Muskrat info (0.00)
Posted by Legendre on 2006-03-18, 07:28:15 (66.41.8.98)
You're half right.. 'Muskrat Love' was written by Willis Alan Ramsey in 1971 and appears on his album "Shelter" as "Muskrat Love (Muskrat Candlelight)". America did a cover of it on their album "Hat T .......
344: Vinyl Asylum, I don't write the songs! (0.00)
Posted by Legendre on 2006-03-17, 19:44:04 (66.41.8.98)
My favorite part of the mid-70's megahit "I write the songs" by Barry Manilow, is that he did in fact *not* write that song. .......
345: Vinyl Asylum, Re: Oooga-chukka, OOoga, OOoga, OOOga-chukka, OOOga, OOOga... (0.00)
Posted by Legendre on 2006-03-17, 19:37:56 (66.41.8.98)
Haha, I had them as "Shocking Blue" but I'm pretty sure you are correct. This one made my shortlist too, for the innapropriate caveman. I'm only 36, so much of this is fuzzy memories of my youth. This .......
346: Vinyl Asylum, Here's a few from the dumpster (0.00)
Posted by Legendre on 2006-03-17, 19:26:25 (66.41.8.98)
Hocus-Pocus - Focus (WTF LOL?!?!) Watching Scotty Grow (Just me 'n God, watching Scotty grow..) Hooked on a Feeling, by Shocking Blue (?) (Inappropriate caveman) Wreck of the Edmund Fitzgerald, by Gor .......
347: Vinyl Asylum, Re: Steve Tibbits "YR" Lida Husik "Joy Ride" nt. (0.00)
Posted by Legendre on 2006-03-16, 20:32:49 (66.41.8.98)
Both the orignal and ECM re-issues of YR are good sounding records. I've got both, but have never bothered with an A/B comparison. If you hunt around, a lot of the Tibbets vinyl is still around, seale .......
348: Vinyl Asylum, Symbiosis "Numinous" (0.00)
Posted by Legendre on 2006-03-16, 07:33:55 (66.41.8.98)
I've got a copy of "Numinous" by Symbiosis, a 12" LP with no 33/45 speed information on it. It plays equally well at either speed, and in fact seems to be designed this way. At 33, it has a dark, fore .......
349: Dynaco-Doctor Forum, Not correct (0.00)
Posted by Legendre on 2006-03-15, 18:45:43 (66.41.8.98)
You're off by one magnitude on the math.. A 10ohm resistor, which is passing 100mA of current, will drop 1.0V - not 100mV. Voltage and current figures are only identical in a 1ohm resistor. If the res .......
350: Dynaco-Doctor Forum, Nice work (0.00)
Posted by Legendre on 2006-03-15, 18:11:22 (66.41.8.98)
The work looks great, and bonus points for being handy and adapting modern terminals to the original phenolic parts. The stock terminals are always a pain on Dynaco ST-70, PAS-3 etc. I'd avoid powder .......
351: Vinyl Asylum, My obvious system (0.00)
Posted by Legendre on 2006-03-10, 16:47:55 (66.41.8.98)
Stuff I've built: - Atma-Sphere M-60 Mk.II power amps, with (mostly) current updates. - Atma-Sphere P-2 preamp, soon to be replaced with MP-1 Mk.II - Legendre Digital (me) SOCD CD transport (software .......
352: Dynaco-Doctor Forum, Re: Groove Tube GZ34 Question (0.00)
Posted by Legendre on 2006-03-10, 16:12:35 (66.41.8.98)
GT doesn't actually manufacture *any* tubes, as far as I know. They just buy generic tubes, then select & re-brand them. To my knowledge, the only new GZ34/5AR4 being made today are the Sovtek, the Si .......
353: Vinyl Asylum, Penderecki on RCA plum label strangeness (0.00)
Posted by Legendre on 2006-03-09, 17:48:56 (66.41.8.98)
I picked up an old but sealed copy of Penderecki's St. Luke's Passion, on RCA (plum label). When I pulled out the discs to look at them, it was obvious that the second disc (sides 2&3) was much lighte .......
354: Vintage Asylum, Re: 6BQ5 amp questions (0.00)
Posted by Legendre on 2006-03-09, 07:25:16 (66.41.8.98)
Wards "Airline" like Sears "Silvertone" were both re-badged house brands, and could have been built by any number of manufacturers over the years. I need to take another look, but my 6BQ5 console set .......
355: Vintage Asylum, Re: 6BQ5 amp questions (0.00)
Posted by Legendre on 2006-03-08, 17:31:13 (66.41.8.98)
This sounds very familiar to me.. I've got an old 6BQ5 based amp from a Wards Airline console, ca. 1959. Same tube complement that you describe, as well as the seperate pre-amp with the umbilical cord .......
356: Vintage Asylum, Looking for Scott tuner knob (non-commercial) (0.00)
Posted by Legendre on 2006-03-08, 17:02:30 (66.41.8.98)
Hey all, I have an elderly friend (mid-80's) who is an avid two-channel guy since before I was born. He's trying to complete a HH Scott LT-110B tuner, and is missing the large center knob for the tuni .......
357: Vintage Asylum, Citation I (0.00)
Posted by Legendre on 2006-03-08, 16:47:04 (66.41.8.98)
I've got a Citation I - the preamp.. but I agree, the II is in a true standout for that era (most eras, for that matter). I've listened to them, but never worked on one. We had one in the shop many mo .......
358: Vintage Asylum, But who is "Slick"? (0.00)
Posted by Legendre on 2006-03-08, 06:29:28 (66.41.8.98)
MIchael, Hmm.. did you look at the OTL Asylum? There is a post from you, that seems to be about an HK Citation II.. right at the top. Things move pretty slowly over there, so it will probably be at th .......
359: Vintage Asylum, Re: Reduced fuse rating in Variac (0.00)
Posted by Legendre on 2006-03-07, 17:56:03 (66.41.8.98)
Sure, you should be able to run a lower fuse value. That fuse is there to protect the variac, not the equipment it's powering. .......
360: Dynaco-Doctor Forum, Re: mklll upgrade board feedback resistor (0.00)
Posted by Legendre on 2006-03-07, 17:00:17 (66.41.8.98)
Changing the feedback resistor can increase / decrease the amount of *gain* in the amplifier, but it has no real effect on how much power it can deliver (to the speakers). Gain and output power are no .......
361: Vintage Asylum, PING MIchael Samra (0.00)
Posted by Legendre on 2006-03-07, 16:51:04 (66.41.8.98)
Michael, Did you lose one of your posts? I found one lying around in the OTL Asylum... Bill PS Did you see my reply, re: what was done on the McIntosh amps? .......
362: Vintage Asylum, Joule Electra (0.00)
Posted by Legendre on 2006-03-06, 17:40:45 (66.41.8.98)
At least one of the Joule Electra OTL amp designs uses a large variac in the AC power supply. So, variacs are OK for daily use in this case. Google `joule electra variac` will bring up two pages of hi .......
363: Vinyl Asylum, good source (0.00)
Posted by Legendre on 2006-03-06, 06:07:24 (66.41.8.98)
Check out: http://www.turntablebasics.com Tim sells every grade of silicone damping oil used in turntables, and he packs it in syringes for dispensing. .......
364: Vintage Asylum, Pong (0.00)
Posted by Legendre on 2006-03-06, 06:00:43 (66.41.8.98)
Hi Michael, First, I should clarify - these MC30 are not mine.. I'm working on this gear for a friend of one of my co-workers. Personally, I use a pair of M-60 Mk.II which I built almost ten years ago .......
365: Vinyl Asylum, The EAR is good (0.00)
Posted by Legendre on 2006-03-04, 07:35:37 (66.41.8.98)
For standalone mag-phono sections, I like the EAR unit. I believe they are switchable for MM/MC, as well. They are nice in stock form, but take very well to modding with upgraded parts, additional byp .......
366: Dynaco-Doctor Forum, Re: PAS3X caps (0.00)
Posted by Legendre on 2006-03-03, 06:25:37 (66.41.8.98)
No problem at all going to 4700uF. I assume that you are planning to rebuild the entire filament supply? Don't waste your time hanging new caps on the old selenium rectifier - they are almost always b .......
367: Vintage Asylum, Re: Panic sets it for a moment (0.00)
Posted by Legendre on 2006-03-02, 16:22:21 (66.41.8.98)
Oops, lol. Why not just use one of the microfiber brushes as sold by Audioquest or www.turntablebasics.com? Cheaper than canned air, and much safer.. as long as you don't keep a hairbrush near the tur .......
368: Tube DIY Asylum, Jensen are excellent, at any price (nt) (0.00)
Posted by Legendre on 2006-03-02, 16:12:31 (66.41.8.98)
nt .......
369: Dynaco-Doctor Forum, Illinois Capacitor (0.00)
Posted by Legendre on 2006-03-02, 06:56:02 (66.41.8.98)
Check out http://www.illinoiscapacitor.com They make a broad line of aluminum electrolytics, and several 330uF/450 snap-in types, in 85c and 105c ratings. Product quality is excellent, and they are le .......
370: Dynaco-Doctor Forum, Re: Pas-3x running "hot" on right channel (0.00)
Posted by Legendre on 2006-03-01, 06:07:21 (66.41.8.98)
There are a couple of possibilities, but the volume control isn't one of them. First, you need to use a meter, and see if you have any DC at the output of the 'warm' channel on the PAS. From the cente .......
371: Dynaco-Doctor Forum, Re: Input impedance of ST-70 with upgrade driver (0.00)
Posted by Legendre on 2006-03-01, 05:45:31 (66.41.8.98)
If you're talking about Joe's basic upgrade board, the input impedance is 150K. You can see it on the schematic: http://www.dynaco-doctor.com/st-70-csl-sch.jpg The inputs are 7,8 and 10,17 Since tubes .......
372: Vintage Asylum, Re: berners (0.00)
Posted by Legendre on 2006-02-28, 17:53:18 (66.41.8.98)
docw, That's brilliant.. thank you! .......
373: Vintage Asylum, McIntosh C20 schematic needed (0.00)
Posted by Legendre on 2006-02-28, 12:26:48 (63.225.146.247)
Ugh.. apparently, there is a preamp with these MC30s. This is what I get for doing favors ;-) Can someone direct me to a schematic (and possibly service data) for a McIntosh C20 preamp? .......
374: Vintage Asylum, Thanks both of you (0.00)
Posted by Legendre on 2006-02-28, 12:22:53 (63.225.146.247)
Thanks again for the help on this. This is actually the first set of Macs I've ever worked on, and I'm trying to do it 'right' and learn a thing or two in the process. FWIW, they are very easy to work .......
375: Vintage Asylum, McIntosh MC30 questions (more) (0.00)
Posted by Legendre on 2006-02-28, 07:11:30 (66.41.8.98)
I've replaced the old selenium rectifiers in these amps with silicon diodes. Voltages on the negative bias supply caps rose from -370 to -410 volts; I guess those seleniums were really hosed. Voltages .......
376: Dynaco-Doctor Forum, Re: install a polarized cap on joe's mklll uprgrade board (0.00)
Posted by Legendre on 2006-02-27, 17:12:08 (66.41.8.98)
Positive end to R6, negative end to R1. This is based on the schematic at: http://www.dynaco-doctor.com/Mk-3-csl-sch.gif .......
377: Dynaco-Doctor Forum, Re: ST-70: EL34s - 2 Duets or 1 Quad? (0.00)
Posted by Legendre on 2006-02-27, 16:54:18 (66.41.8.98)
In terms of the amplifer being happy, all you really need is two matched pairs. But, for best sonics, you should go with a matched quad. This way, both channels will have closer response characteristi .......
378: Dynaco-Doctor Forum, Re: Does painting a rusted chassis diminish its value? (0.00)
Posted by Legendre on 2006-02-27, 08:03:52 (66.41.8.98)
Carl, IMO, the equipment we're discussing is 40+ years old and really shouldn't look 'new' at this point. Exactly how bad is the chrome? A pad of #0000 steel wool can work miracles on old chrome, that .......
379: Dynaco-Doctor Forum, Re: 1/4 watt resistors OK for PAS signal path? (0.00)
Posted by Legendre on 2006-02-27, 07:43:04 (66.41.8.98)
I'm not sure why you would want to use 1/4W devices in the first place. One well-known way to keep resistors sounding good is to keep the current density low (use over-rated parts). But to answer the .......
380: OTL Asylum, Re: Atma-Sphere & Green Mountain Audio (0.00)
Posted by Legendre on 2006-02-25, 08:47:11 (66.41.8.98)
One of the posters here, "chosenhandle" owns both Atma-Sphere and Green Mountain equipment. Not sure if they were / are used in the same system, though. .......
381: Vintage Asylum, Re: Capacitor questions (0.00)
Posted by Legendre on 2006-02-25, 07:26:39 (66.41.8.98)
Just a thought, I don't know how this can is mounted, but normally they make ground by way of soldering one of the twist lock terminals to the chassis or to a metal mouting wafer that is riveted to th .......
382: Vintage Asylum, Re: McIntosh MC30 bias question (0.00)
Posted by Legendre on 2006-02-25, 07:11:11 (66.41.8.98)
Michael, Thanks for the reply. I'm really hoping that I don't have to change out the coupling caps in this unit, but if it comes to that, what are the best replacements that will sound like the origin .......
383: Vintage Asylum, Re: McIntosh MC30 bias question (0.00)
Posted by Legendre on 2006-02-25, 07:03:15 (66.41.8.98)
Ryan, Thanks for that excellent info on repairing the bias circuit. I was suspecting that the old part was a selenium, and that there would be voltage issues if I just swapped it out for a 1N diode. A .......
384: Vintage Asylum, McIntosh MC30 bias question (0.00)
Posted by Legendre on 2006-02-24, 20:09:30 (213.84.43.3)
I'm rebuilding a pair of McIntosh MC 30 amps, and I have a couple of questions. These amps have a single solid-state rectifier in the circuit, used to derive a negative bias supply for the output tube .......
385: Dynaco-Doctor Forum, Re: Hookup wire size? (0.00)
Posted by Legendre on 2006-02-22, 09:25:56 (63.225.146.247)
I'd vote neither. Try to find an *untinned* 20ga solid-core wire. Radio Shack (if they still exist) sold a wire like this, but it may have been 22ga. Just don't go any larger than 20ga - this size is .......
386: Tube DIY Asylum, Re: Which pin is which on a hexfred?? (0.00)
Posted by Legendre on 2006-02-20, 07:33:55 (66.41.8.98)
If it's a 3-legged device, the center leg is the cathode. If it's a 2-legged device, the leg with the small dogleg attached to it is the cathode. .......
387: OTL Asylum, Re: Hum problem solved (0.00)
Posted by Legendre on 2006-02-20, 07:25:57 (66.41.8.98)
JFP, By installing the shorting plug in the 2-3 position, you tied the RCA jack to both the inverting and non-inverting inputs in the amp. This would effectively prevent the amp from amplifing any sig .......
388: OTL Asylum, Re: AARP is an old analog synth, isn't it? /nt (0.00)
Posted by Legendre on 2006-02-18, 07:08:11 (66.41.8.98)
No, you're thinking of the 2600, which was a video game system built & sold by Atari in the early-mid 70s. .......
389: Tube DIY Asylum, Re: Mic pre comments invited (0.00)
Posted by Legendre on 2006-02-17, 16:40:33 (66.41.8.98)
Just a guess, but the feedback loop looks like a tone/eq control to me. If it were a standard NFB loop, I'd expect the resistor to be bypassed with the cap, not in series with it. FWIW, 0.1uF driving .......
390: Tube DIY Asylum, Re: HT standby and triode/UL mode switch ... (0.00)
Posted by Legendre on 2006-02-17, 16:35:48 (66.41.8.98)
FWIW, I see this type of thing done with standard 250VAC toggle switches all of the time. Switch ratings are usually more about the contacts, than about the dielectric properties. Hi-pot test values a .......
391: Tube DIY Asylum, Re: Some numbers.... (0.00)
Posted by Legendre on 2006-02-17, 07:02:38 (66.41.8.98)
(Chiming in..) I could be mistaken, but IIRC all of the 1N400X series diodes are rated for 1A continuous, not 2.5A. These are the cheap, reliable workhorses of rectification, costing around $0.10/ea i .......
392: Dynaco-Doctor Forum, Re: Left Channel Fade Out in PAS? (0.00)
Posted by Legendre on 2006-02-15, 08:04:28 (66.41.8.98)
From what I recall of the stock PAS linestage, the quad cap is common to both channels - so not a likely source of trouble. First thing I'd do, would be a general cleaning of all the pots and switches .......
393: OTL Asylum, Fifty years - can you believe it? (0.00)
Posted by Legendre on 2006-02-15, 07:40:48 (66.41.8.98)
Yesterday, February 14th 2006, was Ralph K's 50th birthday. Seems almost impossible, yet the numbers don't lie. (Also, several individuals at a small party confirmed the fact.) Ralph - Thanks for all .......
394: Tube DIY Asylum, Re: Anyone here use PicoScope(tm) Computer O'Scope? (0.00)
Posted by Legendre on 2006-02-11, 08:34:58 (66.41.8.98)
Too bad it only works with MS Windows.. that alone is enough to keep me away from it. Funny part, is that Pico claims to offer Linux drivers for its products, but if you go to the Linux driver page, t .......
395: Vinyl Asylum, Re: All MP3s are not created equal (0.00)
Posted by Legendre on 2006-02-11, 08:05:26 (66.41.8.98)
I'm not sure what you mean by 'many different codecs'. There are codecs other than MP3 (ogg, aac, wma, flac, shn) but afiak, all MP3 codecs are implementations of the same methods devised by Fraunhofe .......
396: Dynaco-Doctor Forum, Re: it's a 2a3 (0.00)
Posted by Legendre on 2006-02-11, 07:37:19 (66.41.8.98)
Ack, my bad.. yes, a 2A3 type it is. I was working with a prototype guitar amp at work, which used a pair of these 6B4G triodes in P-P. That amp was making around 12-14W at clipping, but of course the .......
397: Dynaco-Doctor Forum, How much power? (0.00)
Posted by Legendre on 2006-02-10, 06:16:35 (66.41.8.98)
Correct me if I'm wrong, but isn't the 6B4G an octal-base version of the #45 triode? How much power does the amp produce (into 8ohms) with this tube? .......
398: Dynaco-Doctor Forum, Re: Any benifit to upgrading the trannies in the PAS or ST-70 (0.00)
Posted by Legendre on 2006-02-08, 16:02:45 (66.41.8.98)
I'd have to agree fully with Bill on this one.. The trannies are what really 'make' the Dynaco power amps. This is why it's so worthwhile to make and install various signal board and PSU mods.. you've .......
399: Dynaco-Doctor Forum, New set failed in one hour (0.00)
Posted by Legendre on 2006-02-08, 15:35:32 (66.41.8.98)
Welp, blow and behold... The previously mentioned quartet of Russian 'Mullard' EL34s went down about an hour after they were installed. The amp suddenly started making a loud hum, and one of the plate .......
400: Dynaco-Doctor Forum, Re: Might have found the trouble...Joe? (0.00)
Posted by Legendre on 2006-02-08, 08:50:20 (66.41.8.98)
Pin 6 is unused on the EL34, so it's being used as a convenient mounting / tie point for the 30ohm resistors. Pin 8 is the cathode, so it's safe to say the resistor is in the cathode circuit. With one .......
401: Dynaco-Doctor Forum, Follow up (0.00)
Posted by Legendre on 2006-02-08, 08:25:31 (66.41.8.98)
Got the choke from Triode (via USPS Priority Mail) and installed it yesterday. Fit perfectly, and seems to work just fine - no hum or buzz. In fact, the unit is pretty well dead silent, even on 102dB .......
402: Dynaco-Doctor Forum, Re: PAS hum (still) (0.00)
Posted by Legendre on 2006-02-08, 08:20:52 (66.41.8.98)
Aaron, Believe it or not, that crazy volume control taper was one of Dynaco's patented 'inventions'. And no, I don't see the point of it either.. pretty obnoxious if you ask me. I've replaced the stoc .......
403: Dynaco-Doctor Forum, Re: "New issue" Mullard EL34s...reliability issues (0.00)
Posted by Legendre on 2006-02-06, 19:50:56 (66.41.8.98)
I just bought two matched pairs of these tubes for an ST-70 that I've rebuilt. Fired up the amp, set the bias and spent an hour listening to it. All is well so far, but if anything goes wrong I'll rep .......
404: Vinyl Asylum, Source (0.00)
Posted by Legendre on 2006-02-04, 18:24:53 (66.41.8.98)
I'm pretty sure that Tim at www.turntablebasics.com has them. Might not be on the site, but he sold me one. .......
405: Dynaco-Doctor Forum, Re: Bias trouble on ST-70 with premium mod (0.00)
Posted by Legendre on 2006-02-04, 08:19:39 (66.41.8.98)
Sounds like a kettle of fish.. you're in a tough spot, with respect to troubleshooting. You'll have to start eliminating variables, to get a grip on the issue(s) at hand. First, anytime a power amplif .......
406: Vinyl Asylum, Re: Almost anything would be better than the brown string (0.00)
Posted by Legendre on 2006-02-03, 16:02:53 (66.41.8.98)
For some reason I was remembering the bearing as bronze, but I'll take your word for it. Didn't even know about the sacrificial Delrin thrust piece in the bottom. If you tip the bearing upside-down, w .......
407: Vinyl Asylum, More Empire 208 musings (0.00)
Posted by Legendre on 2006-02-03, 09:48:46 (66.41.8.98)
First, thanks to everyone who posted comments and suggestions in my previous "Built a new 208" thread. The enthusiasm here is truly heartwarming. But on to other areas of inquiry... I'm curious if any .......
408: Dynaco-Doctor Forum, Re: Replasement of El34 (0.00)
Posted by Legendre on 2006-02-03, 09:24:56 (66.41.8.98)
Nicky, Forgot to mention that a bad coupling capacitor (the one running to the grid of the questionable output tube) can also cause this. It's possible that the cap is slowly developing leakage over t .......
409: OTL Asylum, Re: The dreaded ' blown fuse links ' ? (0.00)
Posted by Legendre on 2006-02-03, 09:18:09 (66.41.8.98)
This is the most common cause of a _totally_ dead tube, yes. If either of the two links are blown, the tube should be replaced. .......
410: Dynaco-Doctor Forum, Re: PAS-3 is non-inverting, definately not stock (0.00)
Posted by Legendre on 2006-02-02, 10:07:54 (66.41.8.98)
I can think of at least one PAS-3 linestage mod that uses two tubes, but does in fact invert the phase. The type of mod done by Atma-Sphere (and probably others) uses a single 12AU7 for each channel. .......
411: OTL Asylum, Re: Two questions about Atma-Spheres (0.00)
Posted by Legendre on 2006-02-02, 09:56:29 (66.41.8.98)
Either method of connection is acceptable for the CD, and there should be no sonic differences. The DC offset issue is something that pops up once in a while, and is related to variances in tube manuf .......
412: Vinyl Asylum, Re: OK. I looked myself up. Part 2 (0.00)
Posted by Legendre on 2006-02-01, 16:20:36 (66.41.8.98)
Well thank you, Kal. I have to admit - there are plenty of projects to keep me occupied, but down the road I might have to look into this option. Best, Bill .......
413: Dynaco-Doctor Forum, Re: Turn off PAS preamp or leave on? (0.00)
Posted by Legendre on 2006-02-01, 07:57:42 (66.41.8.98)
I've owned a modded (Atma-Sphere style) PAS-3 for many years, and crazy as it might sound, I think it ran almost continuously over the course of about seven years. The power switch is bypassed, so you .......
414: Dynaco-Doctor Forum, Re: New Dynaco Owner/ How to use a Variac (0.00)
Posted by Legendre on 2006-02-01, 07:02:22 (66.41.8.98)
Not sure I understand the question re: warming up the amps with a variac. Variacs are generally used for testing purposes, and as an aid to reforming old electrolytics. But if the amps are working wel .......
415: Vinyl Asylum, Re: Try to get a job reviewing analog for Stereophile. (0.00)
Posted by Legendre on 2006-02-01, 06:14:02 (66.41.8.98)
Heh, or perhaps "It has become the new reference" (a review term, which means "We didn't pay for it, and we're not giving it back"). But seriously, I'd really like the opportunity to try one of these .......
416: Dynaco-Doctor Forum, Re: Replasement of El34 (0.00)
Posted by Legendre on 2006-01-31, 17:44:35 (66.41.8.98)
Sounds like either the bias pot is bad, or the tube is gassy. Check the bias voltage on the output tube grid, when current is set correctly. If the current creeps up over time, but the voltage is the .......
417: Vinyl Asylum, Base mod ideas (0.00)
Posted by Legendre on 2006-01-31, 16:46:56 (66.41.8.98)
Yes, that is the stock base. I've considered the possibilitles of replacing it, but I like the look so much that I'm a little hesitant to do anything. That said, here are a couple of ideas for modding .......
418: Vinyl Asylum, Re: am I the only person... (0.00)
Posted by Legendre on 2006-01-31, 16:23:29 (66.41.8.98)
hardy, I'm with you on that.. I love the Grado products. I've used Grados for 10+ years, and they are unbeatable for the money. For a few bucks more, their entry level wood-body carts are astounding. .......
419: Vinyl Asylum, Here's a photo (0.00)
Posted by Legendre on 2006-01-31, 15:44:29 (66.41.8.98)
Here's a (not very good) pic of the new table.. As you can see, it's a 'sleeper'. Other than the TriPlanar, the only clue is the Atms-Sphere logo, partially hidden by a record brush. Also visible are .......
420: Dynaco-Doctor Forum, Re: Here is a reliable source (0.00)
Posted by Legendre on 2006-01-31, 12:10:46 (63.225.146.247)
Bill, Thanks, I went ahead and ordered one from Joe, at Triode. .......
421: Vinyl Asylum, Re: Atma-sphere quotes a price of (0.00)
Posted by Legendre on 2006-01-31, 07:52:55 (66.41.8.98)
To duplicate this table, it would cost roughly $7,000, not including the cost of the original table. And yes, the arm is the significant cost. But, here's the deal.. I've worked in the industry over t .......
422: Vinyl Asylum, Re: You said it youself (0.00)
Posted by Legendre on 2006-01-31, 06:55:15 (66.41.8.98)
Ok, fuzzy memory is starting to creep back.. I think I had *two* different Rek-O-Kut tables in the past; one was a Rondine (does that sound correct?). I think that was the idler drive unit. Motor was .......
423: Vinyl Asylum, Re: Photos! ):[ (0.00)
Posted by Legendre on 2006-01-31, 06:42:17 (66.41.8.98)
Well, it's not that much to look at.. looks like a nice 208 with a TriPlanar on it ;-) The only other giveaway that something is 'up', is the presence of an Atma-Sphere logo on the plinth. I'll try to .......
424: Vinyl Asylum, Re: wow! (0.00)
Posted by Legendre on 2006-01-30, 19:15:57 (66.41.8.98)
Kal, Can you tell me more about the electronic drive for the motor? I always thought the cap was only for starting.. Electronic drive corrects for power factor issues, or? .......
425: Vinyl Asylum, Re: Just built a 'new' Empire 208 - wow! (0.00)
Posted by Legendre on 2006-01-30, 18:56:19 (66.41.8.98)
I'm lightly familiar with the older Rek-O-Kut tables, and yes.. they knew what they were doing. I once owned one of their idler-drive broadcast tables. Too much motor noise for hi-fi use, but it was v .......
426: Vinyl Asylum, Just built a 'new' Empire 208 - wow! (0.00)
Posted by Legendre on 2006-01-30, 18:03:11 (66.41.8.98)
After living with ordinary Japanese tables for 10+ years, I finally built something that works really well. Just wanted to share what I've done. Started with a stock Empire 208 table, with silver fini .......
427: Dynaco-Doctor Forum, Need stock ST-70 choke (0.00)
Posted by Legendre on 2006-01-30, 17:27:09 (66.41.8.98)
Does anyone have a stock ST-70 choke (used is just fine..) that they can sell or trade off? I'm fixing up an old ST-70 for a customer, and the choke is missing from the chassis. Thanks in advance, ple .......
428: OTL Asylum, Re: What Harvey did... (0.00)
Posted by Legendre on 2006-01-12, 17:27:06 (66.41.8.98)
Lew, I think you summed it up pretty well. I'd also add, that in addition to all the changes you mentioned, HR also replaced the bipolar HV supplies in the M-60s with external vacuum-tube regulated po .......
429: OTL Asylum, Re: Upgrade MA-1 Mk. II.2? (0.00)
Posted by Legendre on 2005-12-29, 08:42:28 (66.41.8.98)
The change from Mk. II.3 to Mk. III is primarily a cosmetic change, to bring the MA-1 style into line with the rest of the Mk.III gear. All of the advancements and refinements of the entire Mk.II era .......
430: OTL Asylum, Re: designs for a DIY 6336A amp? (0.00)
Posted by Legendre on 2005-12-08, 16:07:19 (66.41.8.98)
John, I take it that your 50ohm speaker is relatively efficent? I just ask this, because due to the lower (200ohm) Rp of the 6336, you shouldn't need more than 4 power tubes to get the Zout low enough .......
431: OTL Asylum, Re: Differences between M60 and MA* amps (0.00)
Posted by Legendre on 2005-11-15, 08:04:31 (66.41.8.98)
Vesa, To clear up one small point, the "M" in M-50/M-60 refers to "Monoblock", whereas "MA" in MA-1/MA-2 refers to "Music Amplifier" as you correctly stated. The original M-50 had several cost-cutting .......
432: OTL Asylum, Re: I use the V2 jumper too... (0.00)
Posted by Legendre on 2005-10-10, 16:51:16 (66.41.8.98)
My speakers are not hugely efficient, around 93dB or so.. and I've always used the V2 jumper. I find that it seems to improve the bass, on my totally stock, original M-60 Mk.II (no revision level). I .......
433: OTL Asylum, Re: What's a Caddock resisotr package? (0.00)
Posted by Legendre on 2005-09-22, 06:11:41 (66.41.8.98)
Mike, Directly from Caddock Electronics.. I work for Atma-Sphere Music Systems (that's what the (M) is about). When last I checked, Michael Percy Audio sold one type of Caddock resistor. They are a di .......
434: OTL Asylum, Re: Hooking up DAC to Atma-Sphere MP-3 (0.00)
Posted by Legendre on 2005-09-06, 16:46:10 (66.41.8.98)
Either will have the same effect.. we regularly do both at the shop. Personally, I'd suggest you go straight into the tape monitors, as it eliminates an additional connector (adapter) that would be ne .......
435: OTL Asylum, Re: What's a Caddock resisotr package? (0.00)
Posted by Legendre on 2005-09-06, 16:37:24 (66.41.8.98)
The difference is not gigantic, but the Caddock pacakge does move the amp further in the right direction. Basically, it gives you 'more of the same' - doesn't change the sonic character, just improves .......
436: OTL Asylum, Re: better detailed driver tubes for M-60 (0.00)
Posted by Legendre on 2005-09-06, 16:32:14 (66.41.8.98)
This is very well discussed, in the not-too-distant past. Try searching the forum, be creative with the search terms. If you still have questions, then feel free to ask! .......
437: OTL Asylum, Re: Cap upgrade for my M60 and MP3 (0.00)
Posted by Legendre on 2005-08-24, 16:03:49 (66.41.8.98)
Lew wrote: The value is probably anyhwere from 0.1 to 0.47 uF. On an MA-1, the standard value is 0.22uF, but 0.10uF is acceptable. On the M-60, standard value is 0.10uF, but 0.047uF is also acceptabl .......
438: OTL Asylum, Re: Question for Ralph on MP1 (0.00)
Posted by Legendre on 2005-08-14, 16:32:37 (66.41.8.98)
Lew, Just curious, what 'higher Gm' tubes were you thinking about for the phono section? The voltages you describe are all within reason, though I've never run an MP-3 or MP-1 above 265V in either the .......
439: OTL Asylum, Re: Custom stereo OTL in progress (0.00)
Posted by Legendre on 2005-08-11, 17:03:51 (66.41.8.98)
While I personally prefer the look of the original M-60 Mk.II, the II.3 chassis is more suitable for this modification. There really isn't enough room on the older style Mk.II to accomodate two extra .......
440: OTL Asylum, Re: Custom stereo OTL in progress (0.00)
Posted by Legendre on 2005-08-09, 14:18:58 (71.34.59.196)
Lew, This is something I've been mulling over. So far, I haven't gone this way for several reasons.. - The filament wiring area is already crowded, and I'm not sure how practical a larger gauge wire i .......
441: OTL Asylum, Re: not to belabor the obvious, but... (0.00)
Posted by Legendre on 2005-08-05, 18:04:23 (66.41.8.98)
On an MA-1 Mk.II, the driver tube is closest to the edge of the chassis, on the same side as the power tubes. On an M-60 Mk.II.3, it is the tube furthest from the front of the amp. While this tube *is .......
442: OTL Asylum, Custom stereo OTL in progress (0.00)
Posted by Legendre on 2005-08-05, 16:22:29 (66.41.8.98)
In the past I've built a few non-standard amps, but it's been years since the last project. We had a used M-60 chassis laying around, and I just couldn't resist trying out something. This one will be .......
443: OTL Asylum, Re: OTL noob questions....be gentle (0.00)
Posted by Legendre on 2005-08-05, 15:13:03 (66.41.8.98)
It can be difficult to convey the sound of an OTl, to someone who has never heard one. OTL amps have a sound that is not overtly similar to either conventional tube or solid-state amplifiers. You migh .......
444: OTL Asylum, Re: Silly question about humidity (0.00)
Posted by Legendre on 2005-07-26, 15:36:25 (66.41.8.98)
Off the top of my head, I assume you're hearing the same difference that one hears between cold vs. hot tubes. The hotter the tube gets, the better it sounds - in general. The speed of sound also chan .......
445: OTL Asylum, Re: Which pre-amp matches well with Atma-sphere M60 Mk2.2? (0.00)
Posted by Legendre on 2005-07-26, 07:15:44 (66.41.8.98)
There isn't any drastic disadvantage to driving an M-60 from a single ended source, at least for the M-60's part of the equasion. You will lose the advantages of a balanced source in the fist-stage vo .......
446: OTL Asylum, Re: Atma-sphere M-60 Mk.III (0.00)
Posted by Legendre on 2005-07-26, 06:44:41 (66.41.8.98)
The new M-60 Mk.III brings together all of the incremental (Mk.II.2, .3 etc) updates and refinements of the M-60 line made in the last several years - and assembles them in a new chassis. The left & r .......
447: OTL Asylum, Re: Help with Atma-sphere MP3 and DC offset (0.00)
Posted by Legendre on 2005-05-24, 09:57:57 (67.40.171.58)
Manuel, Like I said - it's not an issue of pair matching, but matching of the internal sections. If you find a tube that works right in one channel, then just leave it there and try different ones in .......
448: OTL Asylum, Re: Help with Atma-sphere MP3 and DC offset (0.00)
Posted by Legendre on 2005-05-24, 07:51:23 (67.40.171.58)
Manuel, If the DC lights are coming on, it's due to a section mis-match within the tube. The MP-3 likes to see closely matched sections, but it doesn't care if the two output tubes are not well matche .......
449: OTL Asylum, Re: I resemble that remark.... (0.00)
Posted by Legendre on 2005-05-18, 09:50:58 (67.40.171.58)
Ray, Whoa! You still have that set of amps? I was sure they had changed hands by this time (or at least gotten stolen again..), but it's great to know they are still serving you well. I'd be kind of c .......
450: OTL Asylum, Re: This is the OTL Asylum (0.00)
Posted by Legendre on 2005-05-13, 08:01:20 (66.41.8.98)
Well, I guess it depends what your definition of "more" is. If to you, 120 average-sounding watts is "more" than 60 excellent-sounding watts, then you probably shouldn't bother with OTLs. But with a $ .......
451: OTL Asylum, Who owns the 9000 series Atma-Sphere M-50/M-60? (0.00)
Posted by Legendre on 2005-05-13, 07:53:55 (66.41.8.98)
Back in the mid-1990's, I personally built two or three sets of oddball M-50/M-60 from new & salvaged parts. These sets were sold inexpensively as used, refurbished merchandise, after I had played the .......
452: OTL Asylum, Re: Thank you, but your amplifier is out of my range... (0.00)
Posted by Legendre on 2005-05-13, 07:28:21 (66.41.8.98)
I'm with you gentlemen; I cannot fathom the comments about used tube amplifiers. Maybe there is some validity when the equipment is 40 or 50 years old, but even then - if it was made with quality, it .......
453: OTL Asylum, Re: Sorry for an inane question: any SIMPLE O.T.L. amps out there? (0.00)
Posted by Legendre on 2005-05-09, 09:06:42 (71.34.56.6)
Guy, Actually, the Atma-Sphere amps are the picture of simplicity. Single gain stage, one set of coupling caps, integrated bias supply, zero or low negative feedback, two tube types. If you're looking .......
454: OTL Asylum, Re: Electro Harmonix 6SN7 (0.00)
Posted by Legendre on 2005-05-02, 09:51:32 (67.40.171.35)
This tube has been a real disappointment.. When new, they sound absolutely fantastic - to my ears, probably the best 6SN7 I've ever heard. Problem is, after very little service, they start to show def .......
455: OTL Asylum, This might be my fault.. (0.00)
Posted by Legendre on 2005-04-18, 09:05:34 (67.40.171.35)
Late last week I took a call on this exact subject, and I *may* have given the wrong tube position for the jumper plug (V4 is incorrect, V2 is correct - in any event, it's the top tube in the cascode .......
456: OTL Asylum, Re: 6H13C (0.00)
Posted by Legendre on 2005-04-12, 09:34:01 (67.40.171.35)
You are absolutely correct; all Russian '6AS7' are in fact 6H13C. The 6H13C (6N13S in latin script) is an improved version of the 6AS7. I haven't compared the specs recently, but in service, the 6H13C .......
457: OTL Asylum, Re: Reduced bias setting for fewer tubes in atma M60? (0.00)
Posted by Legendre on 2005-04-05, 10:53:35 (67.40.171.35)
- I thought that the recommended bias setting for the 6AS7s was .075 per tube, e.g. 4 tubes = 0.3ma? (Taking this to mean 0.3A or 300mA) This is still reasonable, but on the high side. Our bias specs .......
458: OTL Asylum, Re: Reduced bias setting for fewer tubes in atma M60? (0.00)
Posted by Legendre on 2005-04-04, 08:53:54 (67.40.171.35)
You are absolutely correct in your thinking. (Tubes / 8) * 550 = new bias setting (for M-60) As an example, 4 tubes total would require a bias of 275mA Bill .......
459: OTL Asylum, Re: Biasing MA-1 (0.00)
Posted by Legendre on 2005-03-17, 08:14:03 (67.40.171.35)
This is not a problem; you are concerned with the steady-state figure, not any initial overshoot. Try something: Disconnect the preamp interconnect from the MA-1 before you attempt to set / check the .......
460: OTL Asylum, Re: Unreg or reg PSUs ? any improvment ?! (0.00)
Posted by Legendre on 2005-02-25, 08:24:59 (66.41.8.194)
>I'd like to regulate these input and driver stages with OA2 / OB2 gas reg tubes . For output stages , that's my question : do i go this way or not ?! Assuming you are using the 0A2 / 0B2 in a simple .......
461: OTL Asylum, Re: Ceramic Tube Sockets (0.00)
Posted by Legendre on 2005-02-23, 15:45:16 (66.41.8.194)
>Has anyone tried tweaking/upgrading the tube sockets? If it is a worthwile improvement, I am interested. There is nothing inherently wrong with a ceramic tube socket; this said, it is nearly impossib .......
462: OTL Asylum, Now I wonder who this might be.. (0.00)
Posted by Legendre on 2005-02-23, 10:52:16 (67.40.171.35)
Goes without saying that I did *not* post this, but the flaming troll who did had IP 138.89.30.71 which appears to belong to a Verizon Internet user, possibly operating from Newark NJ. I'm going to go .......
463: OTL Asylum, AC Power (was Re: 6as7 life continued...) (0.00)
Posted by Legendre on 2005-02-18, 12:26:31 (67.40.171.35)
RF and EMI are issues, but one of the major problems caused by what we call 'electronic loads' (computers, audio equipment, flourescent lights) is distortion of the AC waveform.. When the AC waveform .......
464: OTL Asylum, Re: 6as7 life continued... (0.00)
Posted by Legendre on 2005-02-17, 10:46:59 (67.40.171.35)
>I'm going to mail off my 6as7s to a friend and he'll have a listen to them and we'll see if he thinks they sound bad. As several others have mentioned, you would need a set of desperately bagged-out .......
465: OTL Asylum, Re: 6as7 life continued... (0.00)
Posted by Legendre on 2005-02-15, 09:53:53 (67.40.171.35)
>Thanks for the reply, Bill. For those that don't have access to what you have in the factory bench, it's more difficult isn't it? If by 'the factory bench' you mean the old Philco, then I guess the a .......
466: OTL Asylum, Re: 6as7 life continued... (0.00)
Posted by Legendre on 2005-02-14, 13:50:32 (67.40.171.35)
> When is a 6as7 not good? Let's start with the easy ones: - Internal shorts - One or more dead filaments - One or more blown internal links - Loss of vacuum (gassing) - Fractured envelope > What meas .......
467: OTL Asylum, Re: need advise on building a EL 86 power amp (0.00)
Posted by Legendre on 2005-01-24, 13:34:32 (67.40.171.35)
Admittedly, this is a bigger chunk of iron with better specs than I recall from some PA work I've done in the past. But still.. 40Hz is a _full octave_ above what is even considered a lame minimum.. .......
468: OTL Asylum, Re: need advise on building a EL 86 power amp (0.00)
Posted by Legendre on 2005-01-24, 08:41:04 (67.40.171.35)
Hm, as in the style of transformer used to match long-run 70V Public Address lines to a nominal loudspeaker? I'd check the bandwidth of those parts before you get much further along with this line of .......
469: OTL Asylum, Re: AtmaSphere pre-amp puzzle... (0.00)
Posted by Legendre on 2005-01-19, 09:29:37 (67.40.171.35)
Rupe, Ok, I've read over your question a few times, and I think I get the gist of it.. and I think I have a solution. Your comment that using RCA-XLR adapter doesn't work, and requires switching tape- .......
470: OTL Asylum, Re: 310 degrees F!! (0.00)
Posted by Legendre on 2005-01-18, 16:19:20 (66.41.8.194)
I'm sure that 310F is quite possible, I've seen plenty of roasty-looking plastic & micanol sockets over the years. Don't think the 6AS7s ever get quite that hot on the base, tho. Due to the design of .......
471: OTL Asylum, Cautionary tale - Caig ProGold (0.00)
Posted by Legendre on 2005-01-17, 11:45:19 (70.56.174.4)
Hi all, wanted to pass along a story from last week at the factory. Over the years, I've heard Ralph caution customers (and others) against using contact dressing the likes of 'Caig ProGold' on tube s .......
472: OTL Asylum, Control is on the what now? (0.00)
Posted by Legendre on 2005-01-03, 13:51:44 (70.56.174.4)
Ok, I've really mangled this thread.. Don't know what I was thinking but when I saw 'CDP', I thought Passive Volume control. (Yes, I am the brain specialist!) Essentially, I gave the correct answers, .......
473: OTL Asylum, Crossed wires (0.00)
Posted by Legendre on 2004-12-27, 15:47:16 (66.41.8.194)
Hi Paul, I apologize if my last post may have caused some confusion about Atma-Sphere amplifiers, and the S-30 in particular. The standard input impedance of all Atma-Sphere amplifiers is 100Kohm sing .......
474: OTL Asylum, Re: Direct Volume CDP into OTL amp? (0.00)
Posted by Legendre on 2004-12-23, 15:15:43 (70.56.174.4)
There is nothing inherently different about an Atma-Sphere OTL amp, or any OTL for that matter, which would preclude using a simple passive control. This said, you're never going to get that passive t .......
475: OTL Asylum, Re: M60s - disable negative feedback (0.00)
Posted by Legendre on 2004-12-23, 15:01:02 (70.56.174.4)
Hi Bryan, The NFB loop on the M-60 is rather simple. You will see a two conductor red shielded cable that makes a connection from the speaker posts to the input tube, by way of a pair of 2Mohm resisto .......
476: OTL Asylum, Re: Mullard ECC32 for ATMA-SPHERE MA-2 (0.00)
Posted by Legendre on 2004-12-20, 09:20:35 (70.56.174.4)
There are a few notable differences between ECC32 and 6SN7 types: - ECC32 has 950mA filament vs. 600mA for the 6SN7 - ECC32 is rated with a Mu of 32 vs. 20 for 6SN7 - ECC32 is rated for a max plate vo .......
477: OTL Asylum, Are you sure it needs 200uF? (0.00)
Posted by Legendre on 2004-12-13, 09:46:33 (70.56.174.4)
Depending on the amplifier you intend to drive, you may not need anything like 200uF of capacitance. The value of this cap, figured against the Zout of the preamp's output section AND the Zin of the p .......
478: OTL Asylum, Re: SIlly (?) question about A-S MP 3 (0.00)
Posted by Legendre on 2004-12-13, 09:34:11 (70.56.174.4)
It's not a silly question, and to answer it, this is a Very Bad Idea. The DC filament supply in the MP-3 uses simple resistive filtering, and has no other regulation. With all tubes absent from the ph .......
479: OTL Asylum, Re: Rendition Monitor 60 Amp (0.00)
Posted by Legendre on 2004-12-09, 15:37:42 (66.41.8.194)
Got a chance to listen to these this week at Rendition. Sorry to disappoint, but they sound like every other amp Ralph has designed.. ;-) Circuit is quite similar. but differs from Atma-Sphere product .......
480: OTL Asylum, Re: Option one... (0.00)
Posted by Legendre on 2004-11-25, 09:47:57 (66.41.8.194)
Several people have remarked that a 6AS7-only tester with multiple sockets (like 8 at least) would be desirable. The tester could be used as a burn-in rack as well, in either filament-only or under-lo .......
481: OTL Asylum, Re: Atma-Centric tube tester (trial baloon) (0.00)
Posted by Legendre on 2004-11-23, 16:04:52 (66.41.8.194)
The primary reason for making a tester that does both the small triodes and the power tubes, is that the owner might *not* have access to a tester for the small tubes. As far as using the amps themsel .......
482: OTL Asylum, Atma-Centric tube tester (trial baloon) (0.00)
Posted by Legendre on 2004-11-23, 09:06:17 (66.41.8.194)
This is an idea I've been toying with for some time.. building a dedicated tube tester for Atma-Sphere equipment. I'm curious if there would be enough interest to make it worth the while to build & se .......
483: OTL Asylum, Re: M-60 dc offset/ bias run amok (0.00)
Posted by Legendre on 2004-11-17, 09:35:34 (66.41.8.194)
If the problem followed the tubes to the other chassis, then it's safe to assume that the problem is in the tubes. Specifically, the tube in the V4 (driver) position. All Atma-Sphere amps derive the o .......
484: OTL Asylum, To further muddy the waters.. (0.00)
Posted by Legendre on 2004-11-02, 08:09:52 (66.41.8.194)
I was checking a set of tubes for an MA-1 yesterday. These tubes all had the Sovtek name & logo screened on the glass - next to an *etched* Svetlana =C= logo(!) This is the large =C= logo, with 6H13C .......
485: OTL Asylum, Screws (0.00)
Posted by Legendre on 2004-11-01, 15:05:20 (66.41.8.194)
Jack, Glad to hear they got there; hope they help you out. I sent a few extra, as you might have noticed. Bill .......
486: OTL Asylum, Re: Svetlana - would you say more about this? (0.00)
Posted by Legendre on 2004-11-01, 07:56:27 (66.41.8.194)
Hi Rush, If the Svetlana tube is 'preferred', it's certainly not an issue of sonics. As at least one other poster pointed out, there is no discernable difference in sound between the Svetlana / Reflec .......
487: OTL Asylum, Re: 6H13C instead of 6AS7G (0.00)
Posted by Legendre on 2004-10-31, 07:42:25 (66.41.8.194)
As I understand it, the Russians never made a 'true' 6AS7G.. the 6H13C (6N13S in latin script) is a ruggedized, work-alike variant. This is the only tube we have ever shipped with Atma-Sphere equipmen .......
488: OTL Asylum, Re: Domain is working, but some links aren't.... (0.00)
Posted by Legendre on 2004-10-30, 00:51:41 (66.41.8.194)
Correct. When I have a copy of the full site, I will restore it. For now, just wanted to get something up to test out the hosting / DNS. -Bill .......
489: OTL Asylum, Atma-Sphere.com awakening (0.00)
Posted by Legendre on 2004-10-29, 17:15:02 (66.41.8.194)
Just a quick note to let you all know that atma-sphere.com is back online, in limited form. I am still without the current code for the site (...), so we're up & limping with some modified archive cod .......
490: OTL Asylum, Re: Finally got my OTL apart to check suspected bias shift in one channel (0.00)
Posted by Legendre on 2004-10-28, 14:08:46 (66.41.8.194)
If this is an Atma-Sphere style circuit, the output section bias is derived from the cathode voltage of the driver tube; 12AU7 in the old days, 6SN7 today. Compare plate, grid and cathode voltages bet .......
491: OTL Asylum, Re: 12sx7's in the new MA1 Silver Edition (0.00)
Posted by Legendre on 2004-10-27, 15:59:35 (66.41.8.194)
Cousin B, Lew, I feel that I can answer these questions.. The Silver Edition MA-1 has a DC filament supply @ 6.3VDC. The supply is derived with a full-wave rectifier (2 x 8A Schottky diodes) from the .......
492: OTL Asylum, Re: tube count (0.00)
Posted by Legendre on 2004-10-26, 16:29:56 (66.41.8.194)
The ZEROs have the ability to be used in configurations ranging from 1:1.3 to at least 1:5.8. The standard ratios are 1:2, 1:3 and 1:4. They would be useful for a 6AS7 amp with as little as 4 devices .......
493: OTL Asylum, To be fair (0.00)
Posted by Legendre on 2004-10-26, 07:59:02 (66.41.8.194)
To be fair, I've now been told by Ralph that the above is indeed correct, and we have a full archive of the site contents on the way. Frankly, I'd have been surprised if this were *not* the case.. tho .......
494: OTL Asylum, Re: www.atma-sphere.com gone? (0.00)
Posted by Legendre on 2004-10-25, 14:40:18 (66.41.8.194)
>May be it's Blazer's revenge! Well, call it what you will.. but it was done without any prior notice to me. I might add, over the weekend.. a time which it was nearly impossible to get the domain pro .......
495: OTL Asylum, Re: Fact is, some people are repulsed by MP3s... (0.00)
Posted by Legendre on 2004-10-24, 10:15:50 (66.41.8.194)
For what it's worth, MP3 may already be dying. The AAC and WMV formats are making serious headway, both of which have the capacity to sound much more natural than an MP3. The OGG/Vorbis format is also .......
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